|Publication number||US6608951 B1|
|Application number||US 09/722,271|
|Publication date||Aug 19, 2003|
|Filing date||Nov 28, 2000|
|Priority date||Nov 28, 2000|
|Also published as||EP1213802A2, EP1213802A3, US6731837, US20020094159|
|Publication number||09722271, 722271, US 6608951 B1, US 6608951B1, US-B1-6608951, US6608951 B1, US6608951B1|
|Inventors||Lew Goldberg, Marc Le Flohic|
|Original Assignee||Lew Goldberg, Marc Le Flohic|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (8), Non-Patent Citations (14), Referenced by (28), Classifications (12), Legal Events (8)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The present invention relates to the field of fiber amplifiers and lasers and to devices for optically pumping these in order to create a population inversion within an active medium of such amplifiers and/or lasers.
Devices for optically pumping fiber amplifiers and lasers are currently being used in time division and wave length division multiplex fiber communication systems, free space communication systems, remote measurement and sensing, scientific and laboratory experimentation and other applications.
One problem in the design of fiber amplifiers and lasers is to administer pump light to the active medium of the fibers with a power intensity sufficient to produce a reasonable gain.
Transversal pumping schemes popular with lasers in which the active medium has cross section dimensions of at least several millimeters are not straightforwardly applicable to fiber amplifiers and lasers. Due to the small cross section, overall absorption of transverse pumping light in the fiber is low, resulting in poor efficiency. On the other hand, absorption cannot be increased by increasing the concentration of the active species within the host material of the active medium since this may lead to thermal problems, to a narrowing of the gain vs. wavelength distribution and to other undesirable effects.
Accordingly, setups for longitudinally pumping fiber amplifiers and lasers have been studied. For example, in L. Goldberg, I. P. Koplow, D. Kliner, “Highly efficient 4-W Yb-doped fiber amplifier pumped by a broad stripe laser diode”, Optics Letters, volume 24, pages 673 to 675, 1999, it has been shown that longitudinal pumping of a double cladding fiber structure is an effective approach for constructing high power fiber amplifiers and lasers. Similar pumping setups are known from U.S. Pat. No. 4,815,079, J. D. Minelli et al., “Efficient cladding pumping of an Er fibre”, paper Th.L. 1.2, Proceedings of 21st European Conference on Optical Communications, Brussels 1995, and P. Bousselet et al., 26 dBm output power from an engineered cladding-pumped Yb-free EDFA for L-band WDM applications”, paper WG5-1, Optical Fiber Conference San Francisco 2000.
Since the typical dimension of the inner cladding of such a fiber is 100 to 150 μm, non-diffraction limited emission from high power broad area laser diode pumps can be efficiently coupled into such fibers. A 100 μm wide broad stripe laser diode can generate an output power of 2 to 4 W at 810, 915 or 980 nm with long operating life.
The pump absorption coefficient of a double cladding fiber is inversely proportional to the ratio between the inner cladding area and the core area, which is typically in the range of 200:1 to 500:1. Because of this large ratio it is necessary to use very high dopant densities in order to achieve an adequate pump absorption coefficient, which is required to construct a reasonably short amplifier. Excessively long fiber amplifiers are not desirable because of background propagation losses in the gain fiber, increased cost, and signal distortion and interaction caused by nonlinear effects in the fiber core.
High doping densities, can be used with certain dopants, such as Yb, where a concentration of 104 to 2×104 ppm results in a typical cladding absorption coefficient of 1-3 dB/m at the peak Yb absorption wavelength of 975 nm. Erbium is more desirable as an active species for fiber amplifiers due to its usable gain band of 1530 to 1600 nm within the maximum transmission window of common fiber-glass compositions. However, it has been shown by P. Myslinski, D. Nguyen and J. Chrostowski, “Effects of Concentration on performance of Erbium-doped Fiber Amplifiers”, J. Lightwave Tech., v. 15, pp. 112-119 (1997) that in case of Er the concentrations must be kept at least ten times smaller (typically below 1000 ppm) than these values to avoid concentration quenching effects which significantly reduce amplifier quantum efficiency.
A known technology for circumventing this deficiency is Er/Yb co-doping (cf. J. E. Townsend, W. L. Bames, K. P. Jedrzejewski, S. G. Grabb, “Yb-sensitized Er Doped Silica Optical Fiber with High Transfer Efficiency and Gain”, Electronics Lett. v. 27, pp. 1958-1959, (1991) where high Yb concentration (10-20 times that of Er) is used to achieve high pump absorption, and energy absorbed by Yb is efficiently transferred to Er ions. To achieve this efficient transfer, however, the core glass composition needs to have a large P2O5 content. Such gain fibers are difficult to fabricate with low background loss and high quantum efficiency. In addition the presence of P2O5 in the host glass causes substantial narrowing of the gain vs. wavelength distribution, and results in a small signal gain distribution that is much less uniform than that of amplifiers with Er-doped silica host glass cores. This gain non-uniformity makes the Er/Yb co-doped amplifiers unsuitable for WDM applications that require relatively flat gain distribution across a wide wavelength span.
An attractive method for constructing high power Er-doped amplifiers is to use double cladding structures having a small-inner-cladding. Such devices are described in J. D. Minelli, Z. J. Chen, R. L. Laming, J. D. Caplen, “Efficient cladding pumping of an Er fibre”, paper Th.L. 1.2, Proceedings of 21st European Conference on Optical Communications, Brussels 1995, and in P. Bousselet, M. Bettiati, L. Gasca, M. Goix, F. Boubal, C. Sinet, F. Leplingard, D, Bayart, “26 dBm output power from an engineered cladding-pumped Yb-freeEDFA for L-band WDM applications”, paper WG5-1, Optical Fiber Conference, San Francisco, 2000.
A small cladding, and a correspondingly small cladding-to-core area ratio make it possible to achieve high pump absorption with reasonably low concentrations. A maximum Er concentration of approximately 1000 ppm, possible with a host glass with a large Al2O3 content, would result in a core absorption coefficient of approximately 20 dB/m. In a double cladding fiber with an area ratio of A(cladding):A(core)=25:1 to 100:1, this would result in a cladding absorption coefficient of 0.8-0.2 dB/m. Assuming 90% pump absorption, these absorption coefficients are sufficiently high to construct efficient amplifiers with a length of 12 to 60 m, comparable to that of conventional, core-pumped amplifiers. Assuming a typical core diameter of 5 μm these cladding-to-core area ratios require an inner cladding diameter of 25-50 μm. The upper limit of core diameter, as dictated by bend losses and mode mismatch losses when fusion splicing to conventional transmission fibers, is represented by a 0.1 NA core of 10 μm, corresponding to a cutoff wavelength of approximately 1.45 μm. Such a core size would allow larger cladding diameters and/or larger absorption coefficients.
In addition to achieving sufficiently high pump absorption in double cladding fibers, another issue that must be addressed is whether a sufficiently high pump intensity can be achieved to produce a population inversion level required for high gain across the entire usable gain band of the active species. For Er, the threshold pump intensity, required for a 50% population inversion (50% of the ion population is in the upper state 4I13/2) is given by Ith=hv/st=10 kW/cm2, where hv is the photon energy, s=2×10−21 cm2 @ 980 nm is the absorption cross-section and t˜10 ms is the upper state lifetime. To achieve high gain and low noise performance in the amplifier, a population inversion of >80% is desirable, requiring a pump intensity that is approximately 5 Ith, or 50 kW/cm2. For a cladding pumped fiber amplifier with a 50 μm cladding diameter, this requires a local pump power of 1 W. Since in an efficient amplifier the fiber needs to be sufficiently long to allow almost complete pump light absorption, the local pump intensity decreases exponentially as a function of position, causing a decrease in the local population inversion with distance from the front end of the amplifier. As a result, the pump power has to be larger by a factor of 2-3 than the value calculated above for the case of uniform pump intensity distribution. It is difficult to couple such power levels into an end surface of a double cladding amplifier fiber with little loss and with a focus tight enough to ensure that the pump power is essentially coupled into the inner cladding layer and at the same time to avoid damage to the end surface of the fiber due to excessive incident power.
The present invention is a method and apparatus that provides a double cladding fiber taper and an optical pumping device through which particularly high pump power densities can be coupled into a cladding layer of an optical fiber. Embodiments of the present invention maintain a high-level of packaging or coupling alignment tolerance so that they may be easily installed and used in an environmentally insensitive fiber amplifier.
An embodiment of the invention provides an optical pumping device by which pump light at particularly high power densities can be coupled into a cladding of an amplifying fiber, and light amplified by the fiber or to be amplified by the fiber can be coupled into and out of the fiber without a significant modification of the mode structure.
An embodiment of the invention provides an optical pumping device in which the light from a light source is gathered with high efficiency and is coupled into the amplifier fiber with low loss.
An embodiment of the invention provides an optical fiber amplifier and an optical fiber laser that achieve a high gain over a small length of fiber.
An embodiment of invention concerns an optical pumping device for pumping a fiber amplifier or laser, the device comprising a light source and a light guiding section, the light guiding section comprising a first cladding layer surrounding a fiber core. The first cladding layer has a wide diameter portion, a narrow diameter portion and a tapered portion connecting the wide and narrow diameter portions. The light source is arranged to couple light into the first cladding layer at the wide diameter portion. At this portion, a relatively large surface is available for coupling the pump light into the cladding layer at moderate power densities. By having this pump light propagate along the tapered portion towards the narrow diameter portion, the power density of the pump light may be increased to a level that will result in a high dopant population inversion.
A typical diameter ratio of the wide diameter portion to the narrow diameter portion may be in a range of 2:1 to 6:1. Under proper conditions, such a taper concentrates the pump light injected into the wide end of the taper into the narrow end of the taper, thereby achieving an increase in the pump intensity equal to the square of the taper ratio, or a factor of 4 to 36.
In order to avoid any modification in the mode structure of light propagating in a core of the amplifying fiber, it is preferable that the diameter of the fiber core of the light guiding section of the optical pumping device is the same in the wide diameter, tapered and narrow diameter portions.
The ratio of diameters of the first cladding layer and the core in the narrow diameter portion is preferably in a range from 1.5:1 to 10:1, small ratios being preferred for shorter amplifiers. Other ratios, outside of this range may be used.
According to a preferred embodiment, a lateral v-shaped groove is formed in the first cladding layer at the wide diameter portion, and the light source is arranged to irradiate the groove. In particular, pump light from the light source may be incident on a facet of the groove from a side of the wide diameter portion opposite that of the groove. In this way, light incident at a near normal angle with respect to an axis of the light guiding portion may be reflected towards the tapered portion along said axis or at small angles relative to the axis.
In order to avoid loss of pump light during its propagation through the tapered portion, at the pump light may be coupled into the wide diameter portion with a small numerical aperture of 0.05 to 0.2.
For this purpose, a first lens may be provided for gathering light from the light source with a large first numerical aperture in a first plane and focusing it onto the facet of the groove with a second numerical aperture smaller than the first one, preferably in the range of 0.05 to 0.2.
As a pump light source, a broad stripe laser diode may be used. In contrast to low power (100-200 mW) diffraction limited laser diodes having stripe widths of 2-5 micrometers, this type of high power laser diode, typically has a stripe width of 100-200 micrometers which allows it to generate 2-4 W of power.
Since such a laser diode has different angular spreads of its output beam in its junction plane and in a plane perpendicular thereto, a second lens may be provided for gathering light from the light source with a third numerical aperture in a second plane and focusing it onto the facet of the groove with a fourth numerical aperture, the third numerical aperture being smaller than the first one and the second and fourth numerical apertures being approximately the same.
In an embodiment, the first and second lenses are crossed cylindrical lenses.
According to an alternative embodiment, the light source is arranged to couple light into an end surface of the wide diameter portion of the light guiding section. For this purpose, a dichroic mirror may be provided having a reflectivity adapted to combine and/or separate pump light from the light source and a light at an active wavelength of the fiber amplifier or laser.
An optical fiber amplifier may be formed by connecting, preferably fusion splicing, a first end of a gain fiber comprising a first cladding layer and a doped core to the narrow diameter portion of the light guiding section of a pumping device as defined above, in order to propagate pump light from the pump light source through the first cladding layer of the light guiding section into the first cladding layer of the gain fiber.
Preferably, in this optical fiber amplifier, the gain fiber has a second cladding layer surrounding the first cladding layer, the second cladding layer having a lower refractive index than the that of the first cladding layer. In this way pump light losses are avoided which would inevitably occur if the first cladding were directly surrounded by a fiber jacket that typically has a higher refractive index than the cladding. Of course, the number of cladding layers of the gain fiber is not limited to two.
In order to achieve a homogeneous pump power distribution over the length of the gain fiber, a second pumping device of the type defined above can be connected to a second end of the gain fiber, or further pumping devices may be inserted at intermediate locations of the gain fiber.
A dopant of the doped core of the gain fiber is preferably selected from a group of rare earth ions such as Er, Yb, Er/Yb, Nd, and Tm. For amplifiers having a gain distribution in the 1.5 μm range, the doped core may be doped with Er only, so that the core glass may have a small component of P2O5.
A fiber laser having features and advantages similar to those of the optical fiber amplifier explained above can be obtained if the optical gain fiber is equipped with reflectors at its ends.
Further features and, advantages of the present invention will become apparent from the subsequent description, by word and drawing, of preferred embodiments of the present invention.
FIG. 1 is a longitudinal section (plane parallel to the fiber axis) of a fiber amplifier having an optical pumping device according to the present invention.
FIG. 2 is a cross section of the optical fiber amplifier of FIG. 1 taken along the plane perpendicular to the fiber axis.
FIG. 3 is a longitudinal cross section of a light guiding portion of an optical pumping device that illustrates the propagation of light in the tapered portion thereof.
FIGS. 4a and 4 b each show an example of a fiber amplifier having more than one optical pumping device according to the present invention.
FIG. 5 is a longitudinal section of a fiber amplifier comprising an optical pumping device according to a second embodiment of the present invention.
FIGS. 6a and 6 b show examples of fiber lasers equipped with optical pumping devices according to the present invention.
FIG. 7 represents a short fiber amplifier in which a large core double cladding fiber is coupled to an optical pumping device.
FIG. 8 is a longitudinal section of a fiber amplifier having a diode bar as a pump light source.
FIG. 1 shows a fiber amplifier comprising an optical pump device according to a first preferred embodiment of the present invention. It comprises a light guiding section 1 formed of a single mode fiber pigtail, a broad stripe pump laser diode 5 as a light source, and a double cladding gain fiber 6. The light guiding section 1 is made from a single mode fiber having a jacket 8, a cladding 9 inside the jacket and a single mode undoped core 10 at the center of the cladding. In a first portion of the light guiding section 1, at the left-hand side of FIG. 1, this fiber structure is left intact. In an adjacent wide diameter portion 2, the jacket 8 is removed, so as to expose the cladding 9, and a v-shaped groove 12 is formed at one side of the cladding 9.
Adjacent to this wide diameter portion 2, there is a tapered portion 3 in which the outer diameter of the cladding 9 is gradually reduced so that the length of this tapered portion 3 is typically about 100× the diameter of the wide diameter portion 2 and the ratio of the diameter or the wide diameter portion 2 to the diameter of the narrow diameter portion is typically between 2:1 to 6:1 (the “taper reduction factor”).
A narrow diameter portion 4 at the narrow end of tapered portion 3 is connected, for example by fusion splicing, to double cladding gain fiber 6. Alternatively, the light guiding section 1 and the gain fiber 6 may be constructed from one fiber. The diameter of the cores 10, 13 of the light guiding section 1 and the gain fiber 6 are identical, and so are the outer diameters of narrow portion 4 and of inner cladding 14 of the gain fiber 6.
The light guiding section 1 may be formed from a piece of optical fiber for example, by a chemical etching, laser ablation technique or other methods. In order to form the light guiding section by etching, an end portion of a piece of fiber having its jacket removed may be suspended in an etching solution, the solution initially covering what is to become the tapered and narrow diameter portions 3, 4 of light guiding section 1. The fiber is then gradually raised out of the etching solution, so that the total exposure time to the etching solution will increase as the end of the fiber is approached. By controlling the raising speed, the angle of taper may be defined. As an etching solution, solutions of hydrofluoric acid are applicable.
In FIG. 1, portions 2 and 4 are shown to have a finite length with a constant diameter. However, the length of these portions might be reduced to 0. The wide diameter portion 2 in which the v-shaped groove 12 is formed might be tapered just like tapered portion 3.
Pump light is generated by a broad area laser diode 5. Typically such diodes have an emission region of 1×100 μm, but diodes with an emitter width of up to 500 μm are available and can be used. In such a diode, the longer one of the two dimensions of the emission region is parallel to a plane of a diode junction, whereas the shorter one is in a plane perpendicular to the junction. In the plane perpendicular to the diode junction the emission, confined to approximately 1 μm at the diode facet, is diffraction limited and diverges with a large angle, equivalent to a first numerical aperture of typically 0.5. In the plane parallel to the diode junction the emission at the diode facet is 100 μm wide, is spatially incoherent, and diverges at a relatively small angle equivalent to a third numerical aperture of 0.1. As shown in FIG. 1, an optical system 17 is provided in order to efficiently collect the light from the laser diode 5, reduce its divergence angle and focus it onto a facet 18 of the v-shaped groove 12 with a second and fourth numerical apertures. These various numerical apertures are designated as NA1, NA2 in FIG. 1 and NA3, NA4 in FIG. 2.
The v-shaped groove 12 has an orientation perpendicular to the longitudinal access of the light guiding section, its facets are at right angles (90°) with respect to each other, and, in particular, its facet 18 has an angle of 45° with respect to the core, so that pump light incident from the laser diode 5 at a right angle with respect to the core will be reflected essentially parallel to the core towards tapered portion 3.
Reflection may be achieved by total internal reflection at the facet 18, or a reflective coating may be formed on facet 18.
The function of the tapered portion 3 is to reduce the diameter of cladding 9 by a fixed ratio, while preserving the brightness of the pump light in the tapered portion 3. As the light intensity increases as it propagates from the wide to the narrow diameter portion of light guiding section 1, its divergence angle or numerical aperture increases due to multiple reflections at the surface of cladding 9, as becomes apparent from FIG. 3. Since the numerical aperture of the double inner cladding 14 of cladding gain fiber 6 is typically limited to 0.4-0.6, to assure that light in the narrow end of the taper is within this range, the input beam has to have as small a numerical aperture as possible. To obtain such a pump beam, the optical system 17 of FIG. 1 contains two crossed cylindrical lenses; a high NA (>0.5) lens 20 which nearly completely captures diode 5 emission perpendicular to the junction having said first numerical aperture NA1, and focuses it on the facet 18 of the v-shaped groove 12 with a magnification factor of 5-10, resulting in a second numerical aperture NA2 of the incident beam NA=0.05-0.1, and a low NA lens 21 that is rotated by 90° relative to lens 20. In the view shown in FIG. 1, the cylindrical lens 21 is shown as a rectangle, since cylindrical lens 21 does not focus rays propagating in the plane shown in FIG. 1. Similarly, in the perpendicular view shown in FIG. 2, cylindrical lens 20 is shown as a rectangle, since cylindrical lens 20 does not focus rays propagating in that plane. The cylindrical lens 21 collects the light parallel to the junction having said third numerical aperture NA3 and images it on the v-shaped groove 12 with a magnification factor of approximately 1, resulting in a fourth numerical aperture NA4 of the incident beam NA=0.1. With this configuration, a pump beam with a numerical aperture of 0.1 or less is coupled into the wide diameter portion 2 of the light guiding section 1, allowing a taper reduction factor of between 2 to 6.
Using the above-described setup, a coupling efficiency of 90% of pump light from laser diode 5 to gain fiber 6 can be achieved.
Another advantage of the present invention is that it allows the pump coupling to be carried out in the wide diameter section 2 of the fiber instead of a small diameter fiber. The large fiber diameter of the wide diameter section 2 makes it possible to fabricate a v-groove with a large depth and width so that the spot of light formed by the focused laser diode 5 light is intercepted by a relatively large v-groove facet. This large facet area results in a diode-lens-v-groove alignment tolerance increase, approximately equal to the ratio of the wide diameter section 2 to the small diameter fiber diameter. Using an example of a small diameter fiber with a 50 micrometer inner cladding and an 8 micrometers core, and assuming a 5 micrometers distance between the v-groove apex and the fiber core, the maximum allowed v-groove depth is approximately 16 micrometers. Such a small v-groove depth would require a very tight alignment tolerance, only a factor of two better than that associated with single mode fiber pigtailing. On the other hand, a similar fiber with a 125 micrometers cladding in the wide diameter section 2 would allow a v-groove depth of 53 micrometers, a 3-fold improvement over the small diameter fiber case and an improvement of approximately 7-fold over single mode fiber pigtailing. This permits the construction of an environmentally insensitive fiber amplifier or laser.
Other optical systems for achieving the collection and beam conditioning functions described can be used, such as combinations of spherical and cylindrical lenses, or a microlens in which the front and back surfaces constitute crossed cylindrical lenses.
After coupling into the light guiding section 1 at the wide diameter portion 2, the pump light propagates into tapered portion 3 as shown in FIG. 3. In order to avoid power losses in the tapered portion 3 for light propagating in the cladding, the reduction of the cladding diameter has to take place slowly, typically over a distance of approximately 100 times the fiber diameter of wide portion 2. A shorter distance may be used for smaller taper reduction factors (e.g., 50 times the fiber diameter of the wide portion). For example, for a wide portion diameter of 125 micrometers, the taper section 3 length is approximately 100×125 micrometers=12.5 mm. Accordingly, the figures are not to scale, as the full length of the taper section 3 is not shown in the figures. Light propagating in the tapered portion 3 is concentrated into the narrow end while its divergence angle or numerical aperture increases. For meridional rays, the numerical aperture of the propagating light distribution increases by the ratio of the diameter of the wide end of tapered portion 3 to the diameter of the narrow end, while for skew rays the numerical aperture increases slightly more strongly. Since the diameter of core 10 and the refracted index distribution in tapered portion 3 do not vary in the direction of propagation of the light, signal light in the core can propagate unperturbed through the light guiding section 1.
In order for the cladding 9 in the tapered portion 3 to serve as a waveguide, a low refractive index material that may constitute an outer cladding of light guiding section I surrounds the tapered portion 3. Under these circumstances, the tapered portion functions as a double cladding fiber with the pump light confined in the inner cladding surrounding 9 the core. Typically, such a low refractive index outer cladding is a polymer, but air can also constitute such an outer cladding.
The narrow diameter portion 4 of light guiding section 1 may be coupled to the double cladding gain fiber 6 by a fusion splice 22. Ideally, to avoid signal loss at the splice 22, the mode field diameters of the doped core 13 of double cladding gain fiber 6 and the core 10 of light guiding section 1 should be equal, and so should the diameter of cladding 9 at the narrow diameter portion 4 and inner cladding of gain fiber 6.
The length of double cladding gain fiber 6 is chosen to optimize the amplifier efficiency, gain and noise characteristics based on available pump power from the laser diode 5, dopant concentration in gain fiber 6, ratio of diameters of core 13 and inner cladding 14, etc. For example, for a concentration of 1000 ppm and a core diameter of 8 μm and a cladding diameter of 40 micrometers the absorption coefficient is approximately 20 db/m/25=0.8 db/m. To achieve nearly complete pump absorption, a gain fiber 6 length of 10 to 20 m would be required.
The far end of double cladding gain fiber 6 can be fusion spliced to a second single mode fiber pigtail to remove the residual pump light in the cladding 14.
Alternately, according to a second embodiment of the fiber amplifier shown in FIG. 4a, a second pumping device similar to that of FIG. 1 may be coupled to the far end of gain fiber 6 by a second fusion splice 22′. Such an arrangement results in doubling the amount of pump power that can be coupled into the gain fiber 6, making possible a significant increase in amplifier outlet power and population inversion.
Further scaling of the fiber amplifier can be achieved through the use of multiple pumping devices 25, 25′, 25″ located at terminal and intermediate positions of the fiber amplifier and connected in series, as shown in FIG. 4b. In this embodiment, the pumping devices 25, 25′, 25″ are separated by sufficient lengths of gain fiber 6 to absorb the pump light from one device before it can reach the v-groove 12 of the next device.
In the embodiment of FIG. 4b, all laser diodes are shown to illuminate the same facet (the right hand facet) of the respective light guiding portions 1, so that the pump light will always all be either co-propagating or counter-propagating with respect to light to be amplified in the fiber core. Of course, in pumping devices such as 25′ or 25″ that are located at an intermediate position between two lengths of gain fiber 6, the optical system 17 might be arranged so as to focus the light from the laser diode 5 onto the edge between the two facets of its respective groove, or a beam splitter might be provided for directing two beams on the two facets, in order to distribute the light from the laser diode 5 between the two neighboring lengths of gain fiber 6.
Another alternative amplifier configuration is shown in FIG. 5. Here, instead of using the v-groove side pumping arrangement of FIGS. 1 to 4 b, the pump light is coupled into an end surface 30 of the pigtail fiber 32, as shown. In this configuration, the pigtail fiber is also of a double cladding structure, to allow pump light which is coupled into the inner cladding 9 of the pigtail to propagate without significant attenuation to the tapered portion located in the same fiber.
A dichroic beam splitter 31 is interposed between the pump diode 5 and its optical system 17 on the one hand and the end face 30, on the other. This beam splitter 31 is for coupling signal light to be amplified into or amplified light out of the core 10 of the fiber pigtail 32. The beam splitter 31 is highly reflective at the signal wavelength and highly transmissive at the pump wavelength. The end face 30 of fiber pigtail 32 can be antireflection coated at both wavelengths. In addition, in order to further reduce reflections of signal light in the core 10, the end face 30 can be fabricated at a small angle relative to the axis of the fiber pigtail 32.
The optical pumping device of the present invention can also be used to construct a fiber laser. An end pumped fiber laser comprising the end-pumping device of FIG. 5 is shown in FIG. 6a. Here, the end face 30 of fiber pigtail 32 is coated to have high reflectivity at the lasing wavelength of doped core 13 of the gain fiber 6 and high transmission at the pump wavelength. A reflector 33 at the far end of gain fiber 6 completes the fiber laser cavity. The reflector 33 can be highly reflective at the pump wavelength and partially reflective at the lasing wavelength.
A fiber laser can also be made using a Bragg fiber grating in an arrangement shown in FIG. 6b. Here the end face 30 of the fiber pigtail 32 is antireflection coated at the pump wavelength, and the laser mirror is in the form of a fiber grating 35 written into the core 10 of the pigtail fiber.
Of course, the v-groove pumping device of FIGS. 1 to 4 b may also be employed for pumping a fiber laser. In that case, a reflector at end face 30 of fiber pigtail 32 may be fully reflecting at the wavelength of the pump light, too.
In all of the amplifier and lasers described in this invention various core dopants can be used. As already described, Er is of primary interest because of wide use of 1.5 μm amplifiers in fiber communication systems. Fiber amplifiers based on other dopants can also benefit from the high pump powers and intensities made possible by this invention. With conventional double cladding fibers, the relatively low pump intensities make it difficult to obtain sufficiently high population inversion to obtain significant gain in a fiber gain medium that operates on a 3-level type transition. To achieve significant population inversion and gain in 3-level gain media, the pump intensity must be sufficiently high to achieve depletion of the ground state (terminal) atomic level. Er and Yb atomic transitions are of 3-level type at the short end of their gain spectra. The Er transition is almost entirely 3-level for wavelengths in the 1480-1530 nm range, which are of great interest for short band fiber communication systems. Similarly, the Yb transition is almost entirely 3-level for wavelength in the 975-1020 nm range, which are of great interest for pumping of fiber amplifiers and sensing applications. Using conventional double cladding fibers with Er/Yb co-doped cores, the shortest wavelength for getting significant gain is approximately 1530 nm, while the shortest wavelength for conventional Yb doped double cladding fibers is approximately 1020 nm. Using techniques described in this invention amplification in double cladding gain fibers at wavelengths substantially shorter than these values is possible. Other types of commonly used fiber amplifiers, which will also benefit from this invention, are based on Nd-doped silica and Tm-doped silica.
An advantage of this invention is that it allows very short amplifiers to be constructed using core dopants that can be used with high concentrations, such as Yb, Er/Yb, Nd, and Tm. With Yb for example, very high concentrations, corresponding in core absorption coefficients of 1000-2000 dB/m can be used. In a double cladding fiber with an area ratio of R=25, such as would be the case for a 10 μm core and 50 μm inner cladding, this translates into a cladding absorption of 40-80 dB/m, making it possible to build high efficiency fiber amplifiers and lasers as short as 12.5-25 cm (90% pump absorption). Such fiber lasers are required to achieve single mode longitudinal mode emission. Very short fiber amplifiers, because of reduction of nonlinear effects in the fiber core, can be used to generate very high peak power pulses.
Since pumping devices according to the present invention make it possible to pump efficiently, gain fibers having much smaller area ratios than those mentioned above, e.g., with larger core diameters of the gain fiber, can be used so that even shorter amplifiers can be constructed. For a core diameter of 25 μm and a 50 μm diameter cladding the area ratio is R=4, resulting in a cladding absorption coefficient of 250-500 dB/m. Such fibers will allow construction of efficient amplifiers with a length of only 2-4 cm. Although normally such large cores can support many spatial modes, it has been shown by M. Fermann, “Single-mode excitation of multimode fibers with ultrashort pulses”, Optics Lett. Vol. 23, pp. 52-54, 1998 that a single mode seed can excite only the fundamental mode of a large core fiber. Particularly for the case of very short gain fiber length, the fundamental mode can propagate with no significant single mode-to-multimode conversion. In this invention, the single mode seed signal can be provided through the use of a pumping device with a single mode core 10, which is directly spliced to a multi-mode core 13′ of a double cladding gain fiber 6′ as shown in FIG. 7. To improve the small core to large core fundamental mode coupling the cores 10, 13′ can be tapered during the fusion splicing process. When single mode fiber amplifier/laser output is not required the core 10 in the pumping device can be the same size as the large multimode core 13′ in the double cladding gain fiber 6.
As an alternative to a broad stripe laser diode a fiber coupled laser diode bar might be used as a light source of a pumping device for pumping a double cladding gain fiber.
Currently, fiber coupled bars can deliver power of up to 40 W in a 200 μm diameter fiber with a NA of 0.22. As shown in FIG. 8, pump light from a fiber 37 coupled bar 36 can be injected into the inner core 10 of a pumping device using a v-groove 12, or by using an end coupling arrangement similar to that of FIG. 5.
To facilitate coupling of pump light from the pump fiber 37 into the double cladding gain fiber, various optical elements such as lenses can be interposed between the end of the pump fiber 37 and the wide diameter portion 2 with the v-groove 12.
Starting with a 450 μm diameter fiber to fabricate the tapered portion, a taper reduction ratio of 2.5 would allow the power from pump fiber 37 to be efficiently coupled into a 180 μm diameter, 0.55 NA double cladding gain fiber 6, resulting in a pump intensity which is comparable to that achieved with a single 4 W broad stripe laser diode coupled into a double cladding gain fiber 6 with a diameter of 57 μm. The 450 μm diameter of the wide diameter portion 2 of the light guiding section 1 allows a v-groove depth and half-width of approximately 215 μm, which is sufficiently large to allow a small amount of diffractive spreading of the pump light as it travels from the end of the pump fiber 37 to the surface of v-groove 12, as shown in FIG. 8. Because of the relatively large 0.22 numerical aperture of the pump light incident on the v-groove facet surface, total internal reflection at the facet surface will not provide sufficiently large angular coverage, and a high reflectivity coating with a large angular acceptance range might be required to be deposited on the v-groove surface. One of the advantages of the fiber coupled source is that the available power is approximately 10 times greater than that from a single broad stripe laser diode, another is that the pump source is remotely located from the gain fiber 6.
The advantages of the invention include providing a means for achieving a high pump power density in double cladding gain fibers. Using the pumping device of the invention it is possible to construct high power amplifiers at 1.5 μm using Er doping rather than Er/Yb co-doping, allowing a flatter gain distribution required for WDM systems and other applications. The invention also makes it possible to construct such amplifiers using a v-groove side-pumping technique with a large misalignment tolerance, provides access to ends of the double cladding fiber so that conventional single mode fiber pigtails can be fusion spliced to the ends.
Alternative pumping schemes can use bulk lenses to achieve pump beam reduction that is obtained through the use of the tapered fiber region described above. Coupling of the pump light can be achieved through the end of the double cladding fiber using dichroic beam-splitters to combine the pump light with the signal light.
While the invention has been described with reference to the exemplary embodiments thereof, those skilled in the art will be able to make various modifications to the described embodiments of the invention without departing from the true spirit and scope of the invention. The terms and descriptions used herein are set forth by way of illustration only and are not meant as limitations. Those skilled in the art will recognize that these and other variations are possible within the spirit and scope of the invention as defined in the following claims and their equivalents.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US4737004 *||Oct 3, 1985||Apr 12, 1988||American Telephone And Telegraph Company, At&T Bell Laboratories||Expanded end optical fiber and associated coupling arrangements|
|US4815079||Dec 17, 1987||Mar 21, 1989||Polaroid Corporation||Optical fiber lasers and amplifiers|
|US5037172 *||Dec 11, 1990||Aug 6, 1991||Teledyne Industry, Inc.||Fiber optic device with a reflective notch coupler|
|US5048026 *||May 4, 1988||Sep 10, 1991||The Board Of Trustees Of The Leland Stanford Junior University||Fiber optic amplifier|
|US5432876 *||Oct 19, 1992||Jul 11, 1995||Minnesota Mining And Manufacturing Company||Illumination devices and optical fibres for use therein|
|US5854865 *||Dec 7, 1995||Dec 29, 1998||The United States Of America As Represented By The Secretary Of The Navy||Method and apparatus for side pumping an optical fiber|
|US5864644||Jul 21, 1997||Jan 26, 1999||Lucent Technologies Inc.||Tapered fiber bundles for coupling light into and out of cladding-pumped fiber devices|
|US6072811 *||Feb 11, 1998||Jun 6, 2000||Imra America||Integrated passively modelocked fiber lasers and method for constructing the same|
|1||Bousselet, P.; Bettiati, M.; Gasca, L.; Goix, M.; Boubal, F., Sinset, C.; Leplingard, F.; and Bayart, D.; Title: +26 dBm output power from an engineered cladding-pumped Yb-free EDFA for L-band WDM applications; Alcatel Corporate Research Centre; pp. 114-116 France.|
|2||Fermann, Martin; Title: Single-Mode Excitation of Multimode Fibers with Ultrashort Pulses; Optics Letter; vol. 23, No. 1; Jan. 1, 1998; pp. 52-54.|
|3||J.D. Minelly, et al., "Efficient Cladding Pumping of an Er3+ Fibre", Proc. 21st Eur. Conf. on Opt. Comm, ECOC 1995, p.p. 917-920.|
|4||J.E. Townsend, et al., "yb3+ Sensitised Er3+ Doped Silica Optical Fibre with Ultrahigh Transfer Efficiency and Gain", Electronics letters, Oct. 10, 1991, p.p. 1958-1959.|
|5||*||Lens data for Laser Diode Collimating Lenses from http://www.nsgamerica.com, May 8, 2002.*|
|6||*||Lens data for Selfoc Rod Lenses from http://www.nsgamerica.com, May 8, 2002.*|
|7||Martin E. Fermann,et al., "Single-Mode Excitation of Multimode Fibers with Ultrashort Pulses", Optics Letters, vol. 23, No. 1, Jan. 1, 1998, p.p. 52-54.|
|8||Minelly, J.D.; Chen, Z.J., Laming, R. I., and Caplen, J.E.; Title: Efficient Cladding Pumping of an Er3+ Fibre; Proc. 21st Eur. Conf. on Opt. Comm.; pp. 917-920;Brussels.|
|9||Mononobe, Shuji and Ohtsu, Motoichi; Title: Fabrication of a Pencil-Shaped Fiber Probe for Near-Field Optics by Selective Chemical Etching; Journal of Lightwave Technology; vol. 14, No. 10 Oct. 1996; pp. 2331-2335.|
|10||Myslinski, Piotr; Nguyen, Dung; Chrostowski,Jacek; Title: Effects of Concentration on the Performance of Erbium-Doped Fiber Amplifiers; Journal of Lightwave Technology, vol. 15, No. 1 Jan. 1997; pp. 112-119.|
|11||P. Bousselet, et al., "+ 26 dBm Output Power From an Engineered Cladding-Pumped Yb-Free EDFA for L-Band WDM Applications"; Alcatel Corporate Research Centre, OFC 2000, p.p. 114-116.|
|12||Piotr Myslinski, et al., "Effects of Concentration on the Performance of Erbium-Doped Fiber Amplifiers", Journal of lightwave technology, vol. 15, No. 1, Jan. 1997, p.p. 112-119.|
|13||Shuji Mononobe, et al., "Fabrication of a Pencil-Shaped Fiber Probe for Near-Field Optics by Selective Chemical Etching", Journal of Lightwave Technology, vol. 14, No. 10, Oct. 1996, p.p. 2231-2235.|
|14||Title: Yb3+ Sensitised Er3+ Doped Silica Optical Fibre with Ultrahigh Transfer Efficiency and Gain; Electronic Letters Oct. 10th, 1991 vol. 27 No. 21; pp. 1958 and 1959.|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US6801550 *||May 30, 2003||Oct 5, 2004||Bae Systems Information And Electronic Systems Integration Inc.||Multiple emitter side pumping method and apparatus for fiber lasers|
|US6842570 *||Dec 11, 2002||Jan 11, 2005||Northrop Grumman Corporation||Method for coupling diode array light into an optical fiber|
|US7206124 *||Mar 20, 2003||Apr 17, 2007||Luxpert Technologies Co., Ltd.||Gain-providing optical power equalizer|
|US7477666 *||Mar 21, 2006||Jan 13, 2009||Polar Onyx, Inc.||All fiber based short pulse amplification at one micron|
|US7526003 *||May 23, 2005||Apr 28, 2009||Polaronyx, Inc.||Nonlinear polarization pulse shaping mode locked fiber laser at one micron|
|US7529278 *||Mar 31, 2007||May 5, 2009||Polaronyx, Inc.||Nonlinear polarization pulse shaping model locked fiber laser at one micron with photonic crystal (PC), photonic bandgap (PBG), or higher order mode (HOM) fiber|
|US7532792||Mar 2, 2007||May 12, 2009||Crystal Fibre A/S||Optical coupler, a method of its fabrication and use|
|US7748913 *||May 15, 2008||Jul 6, 2010||Fujikura Ltd.||Fusion splicing structure of optical fibers|
|US7941019 *||May 27, 2006||May 10, 2011||Lockheed Martin Corporation||Monolithic pump block for optical amplifiers and associated method|
|US8070341||Dec 18, 2008||Dec 6, 2011||Visteon Global Technologies, Inc.||Light pipe with uniformly lit appearance|
|US8818151 *||Apr 15, 2010||Aug 26, 2014||United States Of America As Represented By The Secretary Of The Air Force||Fiber Pump Signal Combiner|
|US8873134||Mar 12, 2012||Oct 28, 2014||Nlight Photonics Corporation||Hybrid laser amplifier system including active taper|
|US9022037||Sep 12, 2005||May 5, 2015||Raydiance, Inc.||Laser ablation method and apparatus having a feedback loop and control unit|
|US9063289||Jun 30, 2009||Jun 23, 2015||Nlight Photonics Corporation||Multimode fiber combiners|
|US9130344||Jan 30, 2009||Sep 8, 2015||Raydiance, Inc.||Automated laser tuning|
|US9147992 *||Nov 9, 2012||Sep 29, 2015||Coherent, Inc.||High efficiency amplification of pulsed laser output for high energy ultrafast laser systems|
|US9158070||Dec 28, 2011||Oct 13, 2015||Nlight Photonics Corporation||Active tapers with reduced nonlinearity|
|US20020168139 *||Mar 29, 2002||Nov 14, 2002||Clarkson William Andrew||Optical fiber terminations, optical couplers and optical coupling methods|
|US20040114858 *||Dec 11, 2002||Jun 17, 2004||Hiroshi Komine||Method for coupling diode array light into an optical fiber|
|US20050128569 *||Mar 20, 2003||Jun 16, 2005||Nam-Kyoo Park||Gain-providing optical power equalizer|
|US20060120412 *||May 23, 2005||Jun 8, 2006||Jian Liu||Nonlinear polarization pulse shaping mode locked fiber laser at one micron|
|US20060227816 *||Mar 21, 2006||Oct 12, 2006||Jian Liu||All fiber based short pulse amplification at one micron|
|US20080050069 *||Mar 2, 2007||Feb 28, 2008||Crystal Fibre A/S||Optical coupler, a method of its fabrication and use|
|US20090024191 *||Mar 3, 2006||Jan 22, 2009||University Of Washington||Multi-cladding optical fiber scanner|
|US20090074362 *||May 15, 2008||Mar 19, 2009||Fujikura Ltd.||Fusion splicing structure of optical fibers|
|US20140133503 *||Nov 9, 2012||May 15, 2014||Xiang Peng||High efficiency amplification of pulsed laser output for high energy ultrafast laser systems|
|EP2149211A1 *||Apr 17, 2008||Feb 3, 2010||Gonthier, François||Optical fibre amplifier|
|WO2005002005A2 *||May 27, 2004||Jan 6, 2005||Bae Systems Information||Multiple emitter side-pumping method and apparatus for fiber lasers|
|U.S. Classification||385/43, 385/127, 372/6|
|International Classification||H01S3/094, H01S3/067|
|Cooperative Classification||H01S3/06754, H01S3/067, H01S3/094019, H01S3/06745, H01S3/094007, H01S3/094011|
|Nov 28, 2000||AS||Assignment|
Owner name: KEOPSYS, INC., VIRGINIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:GOLDBERG, LEW;LE FLOHIC, MARC;REEL/FRAME:011320/0760;SIGNING DATES FROM 20001127 TO 20001128
|Mar 7, 2007||REMI||Maintenance fee reminder mailed|
|Mar 9, 2007||FPAY||Fee payment|
Year of fee payment: 4
|Mar 9, 2007||SULP||Surcharge for late payment|
|Jan 26, 2011||FPAY||Fee payment|
Year of fee payment: 8
|Mar 27, 2015||REMI||Maintenance fee reminder mailed|
|Aug 19, 2015||LAPS||Lapse for failure to pay maintenance fees|
|Oct 6, 2015||FP||Expired due to failure to pay maintenance fee|
Effective date: 20150819


|FXLAB DEFRACTION FIREWORK LASER|
• View Big Image •
Spectacular display of sound animated or DMX activated interfering red and green lasers dots and lines with fireworks effect. The product features 50 mW @ 532 nm mW green laser and 100 mW @ 650 nm red laser, sound animation, DMX control.
• Laser power: 100mw Red/50mw Green
• Dimensions: 100x300x200mm
From our display. In excellant order. Boxed with lead and instructions. Full 12 month warranty.
Audiotec Stock Code - D173B
Supplier Stock Code - G018EG
Regular Price £175.00
Special Web Price £119.00


Medical Device Qualified Supplier Directory
Applied Precision Inc. Company Profile
3-208 Britannia Road, East, Mississauga, ON, L4Z 1S6, Canada
Qualifications: ISO 9001
Markets Supplied: North America
Applied Precision Inc. has provided customers with 3D digitizing technology solutions for accelerating medical device development and improving quality for more than 10 years. All these technologies are portable and based on highly advanced optical 3D measurement technology. The company's highly skilled team of 3D measurement & CAD specialists have the knowledge and experience to help customers improve the quality of products and get to market faster.


Heine MINI 3000 FO otoscope D-001.70.110
Heine Mini 3000 otoscope range selection guide
|POSITA SKU||HEINE OTOSCOPE||HEINE CODE||LIGHT PATH||LIGHT SOURCE||MAGNIF.|
|HE10-1-1||MINI 3000 DIRECT||D-001.70.210||Direct||XHL Xenon Halogen||3x|
|HE10-1-2||MINI 3000 FO||D-001.70.110||Fibre Optic||XHL Xenon Halogen||3x|
|HE10-1-3||MINI 3000 FO LED||D-008.70.110||Fibre Optic||LED||3x|
Light path:A fibre optic light path provides a wider field of view compared with a direct light path. This is because, with a direct light path, the light source protudes into the otoscope field of view. Whereas, with fibre optic, the light source does not block the field of view and the optic fibre carries the light.
Light source:The LED light source provides many advantages over the XHL xenon halogen light source. Compared to the XHL xenon halogen light source, the LED light source lasts longer with virtually unlimited working life up to 50,000 hours. The LED light source is twice as bright as xenon halogen instruments. Battery life with LED light source is longer compared with xenon halogen light source because LED requires less power.
Mini 3000 FO otoscope
Modern pocket otoscope in a unique, compact design. Can only be used with the mini 3000 handle system.
- Xenon Halogen bulbs for bright illumination and accurate colour rendering.
- 20,000 ON / OFF switch cycles guaranteed.
- Distal fiber Optic (f.O.) Illumination: reflex-free illumination of tympanum and ear canal.
- Viewing window with 3x magnification and optimized casing surface for razor-sharp images and minimal reflection. Swivelling viewing window built into instrument.
- Pneumatic testing of the tympanum mobility by using the insufflation port and an optional connector.
- Attachment clip with integrated on / off switch. Switches off automatically when returned to the pocket.
- Replaceable batteries. size AA, or optional rechargeable battery with mini NT table charger.
- 2-piece handle and head. Easy to maintain, flexible. Compatible with other handles.
- Award-winning design. Maximum quality with minimum dimensions.
- Fiber Optic (f.O.) illumination
- Port for pneumatic testing


Metal Plasmonic Nanostructures Functionalized by Atomic Layer Deposition of 2A Metal-Oxides for Robust High-Quantum-Efficiency Ultrafast Photocathodes
Small Business Information
Euclid Techlabs, Llc
5900 Harper Rd. #102, Solon, OH, 44139-1866
AbstractHigh quantum efficiency (QE) photocathodes are central for efficient photoinjectors and ultra-fast electron microscopes. Current high QE photo cathode materials like GaAs, alkali-tellurides and alkali-antimonides require ultra-high vacuum and even then have a short life time. Moreover, most of these materials require an ultraviolet light source to operate. Photoemission using a light source in the visible can be accomplished with Cs:GaAs; however this cathode has a slow response time. We propose a principally new engineered photocathode which is robust, high QE efficient, operates in visible wavelengths, and has a & lt;100 fs response time. Such a cathode would preserve the current benefits of high QE photocathodes and address future challenges in the field of scientific accelerators as well as aiming at additional commercial applications such as ultrafast microscopy and detection systems. We propose to fabricate a plasmonic base substrate (Au or Ag nanoparticles or nanowires) functionalized by atomic layer deposition (ALD) of MgO and BaO (known as 2A metal oxides) of only few atomic monolayers to lower the work function. The work function is lowered to enable photoemission with visible photons. The plasmonic resonance of the noble metal nanoparticles can be tuned to provide efficient light absorption hence improving the quantum efficiency of the system. Finally, the cathode consists simply of noble metal nanoparticles under a robust oxide coating and is expected to have a long lifetime. In Phase I we will fabricate the proposed cathode in two steps: synthesis of a plasmonic base structure, followed by atomic layer deposition of the functional layer. The cathode then will be characterized by measuring its quantum efficiency, lifetime in terms of vacuum/atmospheric poisoning, and the thermal emittance will be estimated. Applications and benefits: Robust, high quantum efficiency, extended lifetime, ultrafast photocathodes operating at visible wavelengths will significantly improve the beam quality of the photoinjectors for current and future light sources. Besides applications in basic science, the long life of the cathode material and the ability to use a visible laser means that photoinjectors will find a variety of applications in electron microscopy and vacuum electronics. Medical therapy and diagnostic systems will be able to make use of the high quality electron beams generated in a high QE photo-injector without sacrificing the average current.
* information listed above is at the time of submission.


BD LSRII-1 UV Laser Operation
NOTE: If the UV laser needs to be “on” for your experiment (Indo, Hoechst, AF350, CellTrace Calcein Blue AM, LIVE/DEAD Fixable Blue, etc.) please make sure to follow the steps explained below.
- For the first time please make sure to be trained by the FCRC staff on this procedure. Training takes about 5 minutes and no advance scheduling is necessary (business days, 9 am – 5 pm).
- For the following attempts please follow the written instructions below:
- Check if UV laser is “on” or “off” by opening the BD LSRII-1 lid and placing the “gloved” hand into the UV laser path;
- If the UV laser is “on” proceed on step 2d;
- If the UV laser is “off”, you need to turn it “on”:
- Double-click on the “BD Coherent Connection” icon on the desktop;
- When the “BD Coherent Connection” interface fully opens, click the button “Laser ON” and wait a few seconds until the UV laser’s power meter shows 19-20 mW;
- Minimize the “BD Coherent Connection” window (Do NOT close the program);
- Wait 15 minutes for the data acquisition to make sure that the laser is completely warmed-up and stabilized;
- Proceed on the item 5 from the “BD LSRII and BD LSR-Fortessa Maintenance Guidelines”.
- After the data acquisition is finished make sure to switch off the UV laser by maximizing the Coherent icon and clicking “Laser OFF” button on its user interface.


Fraser Optics’ products, uniquely engineered with STEDI-EYE® Technology, give professionals and serious users a competitive edge by eliminating motion and enhancing clarity. Only Fraser Optics offers advanced gyro-stabilized products backed by proven performance in military and law enforcement mission critical operations. All Fraser Optics products have been tested under extreme conditions and are guaranteed to be reliable, precise, and unmatched in operational performance. Fraser Optics will offer premier optical solutions exceeding customer expectations providing the highest standards for quality and satisfaction. They continually learn from their customers in order to improve on future products and services.


Auerbach Das Zeisswerk und die Carl Zeiss-Stiftung in Jena (third edition Jena 1907)
Calculation of glass properties - a significant contribution to the success of the companies Zeiss and Schott
Optical Museum Jena. Life
In 1847 Carl Zeiss started making microscopes full-time. In 1861 he was awarded a gold medal at the Thuringian Industrial Exhibition for his designs.
Raised in Weimar Germany he became a notable lens-maker in the 1840s when he created high-quality lenses that were "wide open" or in other words had a very large aperture range that allowed for very bright images. At first his lenses were only used in the production of microscopes but when cameras were invented his company began manufacturing high-quality lenses for cameras.


Holotomographic microscopy HT 2
Scanning Confocal Microscope A1R+
Andor Neo 5.5 sCMOS Cameras
AvaSpec-HS2048XL Fiber Optic Spectrometers
High speed linear THz camera
Laser-Driven Light Source EQ-400
Nanoscribe – 3D Laser Lithography System
Nikon has a diverse microscope camera and controller lineup, enabling researchers to configure a microscope imaging system that’s ideal for their specimens and applications.
New 16.25-megapixel, high-definition monochrome microscope camera equipped with Nikon FX-format CMOS sensor. Delivers high-sensitivity, low-noise images.
New 16.25-megapixel, high-definition color camera equipped with Nikon’s digital SLR camera FX-format CMOS sensor. Provides superior color reproduction and fast frame rates.
Color camera head with increased frame rates, high resolution acquisition and extremely accurate color reproduction. A microscope camera offering fast, high resolution image capture, with unsurpassed color representation.
5-megapixel cooled color digital microscope camera head ideal for acquiring detailed images under a variety of illumination techniques.
High speed, high sensitivity, microscope camera featuring 2-megapixel color CCD with outstanding SXGA video display rates of up to 27 frames per second.
Versatile and easy-to-use camera control unit provides effortless camera control and microscope operation via mouse or touch panel operation
copyright © 2019 All Rights Reserved By EINST Technology Pte Ltd.


New parallel UV light source, 8.9-inch monochrome screen, high performance Z-axis, 8x anti-aliasing and other features ensures Foto 8.9 print 3d designs accurately and with delicate features, layer thickness at 0.025-0.2mm.
New Parallel Light Source | Higher Print Speeds
Printing 50% Faster
Prints multiple objects at the same time with no time increase.The upgraded Monoscreen allows greater air permeability, which speeds up 3d printing.
New Parallel UV Light Source
Foto 8.9 uses a 405nm-wavelength UV integrated light source. This new parallel UV light source ensures uniforms light distribution, reduces heat, with reliable high performance. Combined with 4K monoscreen, this light source helps ensure a higher printing success rate and finer details of printed 3d objects.
Effective Heat Dissipation System
Double Linear Rails Z-axis System
Equiped with double linear rails, wire rod motor and nuts, the Z-axis linear rails move steadily. This allows Foto 8.9 to eliminate layer lines and riffles on th final 3d prints, showing smooth surfaces and delicate texture.
Supports Multiple Slicers
Foto 8.9 works with CHITUBOX and Flashforge self-developed slicer FlashDLPrint. With its easy operation, 8x Anti-aliasing feature and many more practical functions, Foto 8.9 empowers everyone, even 3d print beginners, to print 3d models with smooth edges and elegant looks.
Larger Build Volume
Max build volume 192*120*200mm meets printing requirements of big and creative designs.
Examples printed with Foto 8.9"


Devitrification Kinetics and Optical Stability of Optical Fibers at High Temperatures
Reliable sensing and monitoring systems based on optical fibers operating at high temperatures and in harsh environments are of high demand. One of the limitations of such systems is the devitrification of the fused silica based core and cladding glass at elevated temperatures. Crystallites can nucleate on the surface of the cladding and grow into the core. The formation of these crystalline flaws in the optical fiber causes stress concentration and extrinsic optical scattering and in addition leads to decreased mechanical properties and reduced optical stability. Commercial optical fibers of different compositions and core-cladding design were characterized in this study with respect to crystallization rate under various conditions. The optical stability was monitored with an optical spectrum analyzer. The crystallites were characterized with SEM and optical microscopy. The activation energies of crystallization for High OH and Low OH multimode fibers were estimated by measuring the crystal growth rate at different temperatures. The residual stress resulting from the formation of the crystals, which can lead to decreased mechanical performance of the fibers, was characterized with polarized light optical microscopy. The influence of water vapor in the atmosphere on the crystallization rate was determined. The features induced in the attenuation spectra were consistent with hydroxyl (OH) absorption peak. Spectral features such as thermal emission and hydroxyl absorption bands are discussed.
The results obtained in this study can be used for selecting optical fibers for high temperature applications.


QPxTool allows scanning the quality of optical discs to predict failures, when used with supported optical dives.
This is a stub entry - I've not used this tool but it looks useful. Later authors should overwrite this text.
 User Experiences
 Development Activity
Andy Jackson (100.0%)


SSG Precision Optronics proposes the development of a novel optical manufacturing process that will allow the production of state-of-the-art Silicon Carbide (SiC) optics. The work proposed combines three different manufacturing technologies, a slip cast SiC mirror forming process and low temperature CVD SiC coating process, which have been developed by SSG, and Computer Controlled Optical Surfacing technology (CCOS) which has been developed by Tinsley, a subsidiary of SSG. The combination of these technologies will provide SiC optics with state-of-the-art surface figures (low frequency and mid-frequency errors will both be addressed) and low-scatter surface finishes. SiC optics offer a number of critical advantages for space-based optical systems. The superior material properties of SiC provide a high degree of lightweighting (70% - 90% of beryllium) and a superior thermal stability (1.5x ? 2.5x better than ULE). The manufacturing process proposed will allow the technical advantages associated with SiC materials to be realized, providing the capability to produce imaging mirrors which are capable of providing excellent accuracies (<0.01 waves RMS), low micro-roughness (< 10 Angstroms RMS), and very low areal densities (~10 kg/m2 at an aperture of 1 meter) while maintaining the thermal stability required for space-based imaging applications. The quality and micro-roughness of these optics will be good enough to address the stressing needs associated with visible, UV and EUV wavebands. In our Phase I work the process development proposed will be verified by the production of a lightweighted SiC aspheric mirror to a set of stressing figure and finish requirements.


Spy Fizz sunglasses are beach and backyard BBQ ready, and we hope that you are too. The Grilamid® frame is lightweight and incredibly durable. The 4-base polycarbonate ARC® lenses for optimal coverage and clarity.
- 100% UV protection significantly reduces eye-fatigue and sun damage
- Innovative lenses enhance contrast and make colors pop
- Free shipping
- Includes a soft storage bag and Spy stickers. Score.
#GoNativeSeeNative @ NativeSlope.com
Delicious deals on the performance sunglasses you crave.
Always low prices. Always free shipping.


The TM-6740GE is a VGA format monochrome progressive scan CCD camera with Gigabit Ethernet output. The Kodak KAI-0340D imager resolution is 640 x 480 pixels at a frame rate of 200 fps in full frame mode, and significantly higher speeds in partial scan and binning modes.
A user-friendly graphical user interface (GUI), provided as part of the camera’s extensive software development kit (SDK), allows users to control various camera functions.
The SDK also provides functions for controlling the grabbing of images, and configuring local I/Os, by means of an integrated API and a set of powerful C++ classes. Changes in the camera’s acquisition modes automatically update the API for easy image acquisition. CPU usage is only a few percent, thanks to the TCP/IP offload engine.
Dimensions (H x W x L): 51 x 51 x 85 mm
640(H) x 480(V) @ 200 fps, 7.4 µm square pixels
Gigabit Ethernet output (8-bit/10-bit selectable)
Partial scan & binning modes up to 3205 frames per second
Maximum dynamic range control through built-in look-up table (8-bit only)
Asynchronous reset, no-delay shutter, with full frame speeds to 1/64,000 sec.


Photographylife.com is reviewing Nikon’s first teleconverters for the Z mirrorless system: the Z TELECONVERTER TC-1.4x and Z TELECONVERTER TC-2.0x. These two teleconverters multiply your focal length by 1.4× and 2.0× respectively, with the usual loss of light. How do they hold up in practice?
Nikon Z TELECONVERTER TC-1.4x and Z TELECONVERTER TC-2.0x reduce the amount of light
If you’ve been around the block, I’m sure you’ve heard that teleconverters come with tradeoffs. The most obvious issue is that they reduce the amount of light a lens can gather. The Nikon Z 1.4x TC loses one stop of light (AKA cutting the amount of light in half), while the Nikon Z 2.0x TC loses two stops of light (cutting the light in fourth).
For obvious reasons, this is a problem in low-light conditions. For example, a popular wildlife photography lens like the Nikon Z 400mm f/4.5 VR S would turn into a 560mm f/6.3 with the 1.4x teleconverter – and into an 800mm f/9 with the 2x teleconverter.


The Vast Camera Glasses are a valuable part of Vast SID. They provide comfort and quality video feed which ensures even better results from the system.
Our designer team has worked hard to bring a stylish and discreet vision of the glasses so they look no different than normal sunglasses yet they include technologies which provide an amazing user-experience. The glasses are light so it will not be a burden but a nice accessory to a person`s style. The camera is neatly built in the frames with only a tiny hole to the side of the glass.
Although the Vast SID mobile app can work alone having the camera at eye-level is much more convenient for the user. People instinctively direct their heads toward what attracts their attention and through the camera glasses Vast will be recording exactly what interest the visually impaired person. Having the cameras on the glasses also means that the smartphone can be left in one`s pocket and have both their hands free. Utilizing the glasses the user can have the ultimate Vast experience and get the best assistance it can provide. Taking full advantage of the features the system has and enjoying life in a more open world.


Designed and open-sourced by vinnycordeiro and whoppingpochard jam the Rainbow Barf Logo LED for StealthBurner
The Rainbow Barf Logo LED is a small PCB, approximately the size of a typical single 5050 WS2812 “Neopixel” PCB, but holding eight miniature protocol-compatible LEDs positioned to match the logo cutout on the StealthBurner.
This gives you the possibility to programmatically address each part of the logo lighting independently! Imagine the possibilities!
You will need new carrier and led diffusers printed parts for this front LED.


DetailsGlobal Vision® Eyewear's Triumphant ??? Frame Safety Glasses with clear lenses that meet ANSI Z87.12010 for Industrial use. Lenses are maximum UV protected, shatterproof polycarbonate, scratch resistant. Vented EVA Foam for Comfort.
- Additional Information
MFG Country Taiwan MFG Global Vision Color N/A Specs what color frames??


Formovie Laser TV 4K Cinema
- Regular price
- Sale price
- Regular price
- Unit price
Tenga en cuenta que este producto utiliza un enchufe estándar de la UE. Se necesita un convertidor si lo usa en otras áreas.
4K resolution UHD
With 4K UHD and bright 2100 ANSI lumens, you can still have a sharp picture with all details on a 100-inch giant screen. An upgrade of viewing experience, you can also enjoy the wonderful pictures indoor daytime.
ALPD® technology, DLP® display technology
With ALPD®(Advanced laser phosphor display technology) and TI DLP® technology, the picture is much clearer, the details are much more vivid and much closer to the real world.
Protect your eyes
The laser source provides an image with greater precision and offers natural viewing while avoiding unwanted light scattering and protecting your eyes. Short throw projector reduces eyestrain by diffusing light without losing picture quality.
Max 150-inch projection screen size
You can easily adjust the throw distance to produce an image of 80''-150''. Now you can watch films, enjoy concerts and play games, all on the same wall.
DTS & DOLBY certified sound quality
Using Dolby Audio & DTS-HD, brings an all-new audio experience through much more natural and lifelike sound effects, creating an immersive acoustics experience.
Certified Android TV 9.0
Officially authorized Android TV, with built-in Chromecast, can support wireless transmission. Simultaneously, the interface is simple and easy to use, and also supports voice assistants.
456 × 308 × 91mm/18 × 12.1 × 3.6in
7.5 kg/16.6 lb
Laser whit ALPD® by Appotronics
2100 ANSI lm
0.23 : 1
Recommended picture size
60’’ to 120’’
60 Hz(120 Hz in 3D)
3,000 : 1
Dolby Audio, DTS-HD
Full-range×2 + Tweeter×2 （30 W in total）
*ALPD®, the laser fluorescent display technology, is based on the technical route of laser-stimulated fluorescence and hybrid multi-color laser for image display. ALPD® is a technology widely used in cinema laser viewing halls.
*4K effect refers to the effect when playing 4K source.
*The adjustable screen size is 40-200 inches, and the recommended screen size is 80-150 inches. The image quality will be lost as the projection area increases.
*Support HDR10 decoding: means that the processor supports HDR10.
*The Rec.709 color gamut format is an international standard for high-definition television (HDTV). All links of filming, production, and broadcasting of film and television dramas are produced based on the Rec.709 color gamut standard. Rec.709 certification.
*Dolby virtual surround and vocal enhancement technology: DOLBY and DTS official technology certification has been obtained, DOLBY certification number: #600017, DTS certification number: C237603.
*25,000 hours is the average service life of the light source, and it is estimated based on the average use of 4 hours per day in a normal environment.


At the cutting edge of innovation, the new SCOTT Spur sunglasses represent a step further in performance eyewear. The innovative design, with its XL lens creating a perfect shield, has had a large focus on protection. The Spur offers maximum coverage in order to protect your eyes from wind and various flying debris from the ground. The low-profile branches are specifically designed to fit well with helmets that have added coverage over the temples for optimal comfort. Additionally, the SCOTT Spur comes with the ELC system which allows you to switch lenses quickly and easily. The Spur is delivered with a spare lens, an adjustable nose piece and a hard case with a micro fiber bag.
|Fit||For medium to large faces|
|Technologies||SCOTT Fusion Frame|
|ELC lens change system|
|No-slip soft nose pads|
|No-slip and flexible temple ends|
|Lens Technologies||SCOTT Precision Optics lens quality|
|Maximal field of vision|
|Extra large lens coverage|
|ACS Air Control System|
|100% UV Protection|
|Extras||Spare clear lens included|
|Hard case with microfiber bag|
Region Carrier Cost Squamish In-store Pickup $0.00 Within BC FedEx 2-Day $12.00 Canada-wide FedEx 2-Day $17.00 U.S. (Continental) FedEx Ground $22.00 International FedEx International Quote
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Did you know … SeeReal’s publication in Applied Optics was selected as a „Spotlight on Optics“ by OSA in May 2017
SeeReal recently published an article in Applied Optics titled „Large real-time holographic 3D displays: enabling components and results“. This publication was now selected as a „Spotlight on Optics“ by the OSA in May 2017. The „Spotlight on Optics“ is a highlighted article that was nominated by editors from various OSA journals .
The article presents the progress of SeeReal’s solution to real-time holography. The concept and components of a real-time holographic 3D display with 14″ active area are described, e.g. laser sources, spatial light modulator and holographic optical elements for beam shaping. The requirements on these components are discussed. Finally, photographs of a holographically reconstructed 3D scene are shown.


We have developed a unique numerical laser model by use of a commercial physical optics software package. The experimentally measured lasing threshold, slope efficiency, power output distribution, and phase front have been derived. This model is particularly powerful for monitoring the effects caused by thermal distortions encountered in power scaling lasers. Extrapolations have been made through parametric studies to predict changes required in the laser design that would optimize the performance of the laser.
© 1998 Optical Society of America
(140.0140) Lasers and laser optics : Lasers and laser optics
(140.3480) Lasers and laser optics : Lasers, diode-pumped
(140.3530) Lasers and laser optics : Lasers, neodymium
(140.5560) Lasers and laser optics : Pumping
Joseph L. Dallas and Robert S. Afzal, "Modeling of a Diode-Side-Pumped Nd:YAG Laser," Appl. Opt. 37, 2365-2370 (1998)


Optical CDMA, radio-over-fiber, optical packet switching, and visible light communications
Assoc. Prof. Kai-Sheng Chen received his B.S. degree in Electrical Engineering from National Central University, Taoyuan, Taiwan, in 2010. He obtained his M.S. and PhD degree from the Institute of Computer and Communication Engineering, National Chen Kung University, Tainan, Taiwan, in 2012 and 2017, respectively. Since 2017, he has been with the Nanfang College of Sun Yat-Sen University, Guangzhou, China, where he is currently an Associate Professor of School of Electrical and Computer Engineering.