Abstract: An optical receiver is described. Using silicon-photonic components that support a single polarization, the output of an optical receiver is independent of the polarization of an optical signal. In particular, using a polarization-diversity technique, the two orthogonal polarizations in a single-mode optical fiber are split in two and processed independently. For example, the two optical signals may be provided by a polarization-splitting grating coupler. Subsequently, a redistribution element provides mixtures of the two optical signals. Next, a wavelength channel in the two mixed optical signals is selected using a wavelength-selective filter (for example, using ring-resonator drop filters or an echelle grating) and converted into an electrical signal at an optical detector (such as a photodetector) to achieve polarization-independent operation.

Abstract: Provided is a waveguide-type optical diffraction grating. A waveguide core includes a waveguide core that is asymmetric with respect to a thickness direction perpendicular to a light propagating direction. In the waveguide core, a phase adjustment portion is configured to adjust a phase difference between a forward wave traveling in an input direction and a reflected wave traveling in a direction reverse to the input direction in the waveguide-type optical diffraction grating, and the phase adjustment portion is provided in a manner that a sum of a phase of the forward wave and a phase of the reflected wave which are generated in the phase adjustment portion becomes a constant value irrespective of a polarization state of input light to the waveguide-type optical diffraction grating.

Abstract: A system for integrated power combiners is disclosed and may include receiving optical signals in input optical waveguides and phase-modulating the signals to configure a phase offset between signals received at a first optical coupler, where the first optical coupler may generate output signals having substantially equal optical powers. Output signals of the first optical coupler may be phase-modulated to configure a phase offset between signals received at a second optical coupler, which may generate an output signal having an optical power of essentially zero and a second output signal having a maximized optical power. Optical signals received by the input optical waveguides may be generated utilizing a polarization-splitting grating coupler to enable polarization-insensitive combining of optical signals. Optical power may be monitored using optical detectors. The monitoring of optical power may be used to determine a desired phase offset between the signals received at the first optical coupler.

Abstract: Polarization rotators of conventional techniques require forming a silicon nitride layer, which is not employed in usual fabrication of a silicon waveguide circuit. In order to employ a polarization rotator function in an optical integrated circuit, a process of forming a silicon nitride layer is added just for that purpose. This increases the fabrication time and complicates the fabrication equipment. In a polarization rotator of the present invention, the waveguide width of a center core portion of a polarization converter is made small. Thus, the intensity of an optical wave does not concentrate only at the center core portion and is more influenced by structural asymmetry. With the configuration of the polarization rotator of the present invention, it is possible to efficiently cause polarization conversion with a structure including only a silicon waveguide and no silicon nitride layer or the like formed thereon.

Abstract: A ring cavity device includes a passive ring waveguide and an input/output waveguide horizontally coupled to the passive ring waveguide, including an active waveguide structure vertically coupled to the passive ring waveguide and/or the input/output waveguide. The active waveguide structure compensates for the loss of the passive ring waveguide. A method for fabricating a ring cavity device is also included. The ring cavity device may obtain part of the gain by vertical coupling or mixed coupling (vertical coupling followed by horizontal coupling) thus to compensate the loss in the ring cavity device. Hence, the quality factor of the ring cavity device is improved.

Abstract: An effective refractive index of a TM0 polarized wave guided through the first core when existing alone and an effective refractive index of a TE0 polarized wave guided through the second core when existing alone are continuous as a function of a distance from a starting point of a side-by-side arrangement section. A magnitude relationship between an effective refractive index of an odd mode of a TE0 polarized wave guided through the side-by -side arrangement section and an effective refractive index of an even mode of a TM0 polarized wave guided through the side-by-side arrangement section is reversed between the starting point and an ending point of the side-by-side arrangement section. A refractive index distribution is vertically asymmetrical in an interaction section.

Abstract: A process for manufacturing a photonic circuit comprises: manufacturing on a first wafer a first layer stack comprising an underclad oxide layer and a high refractive index waveguide layer; patterning the high refractive index waveguide layer to generate a passive photonic structures; planarizing the first layer stack with a planarizing oxide layer having a thickness below 300 nanometers above the high refractive index waveguide layer; annealing the patterned high refractive index waveguide layer before and/or after the planarizing oxide layer; manufacturing on a second wafer a second layer stack comprising a detachable mono-crystalline silicon waveguide layer; transferring and bonding the first layer stack and the second layer stack; manufacturing active photonic devices in the mono-crystalline silicon waveguide layer; and realizing evanescent coupling between the mono-crystalline silicon waveguide layer and the high refractive index waveguide layer.

Abstract: An all-optical fiber sensor apparatus includes a light source and an in-line fiber polarizer that polarizes light received from the light source. The in-line fiber polarizer outputs light in a first polarization state which is directed to a polarization-maintaining fiber. After receiving the light in a first polarization state, the polarization-maintaining fiber transmits the light such that the light exits as light in a second polarization state. During measurements, the polarization-maintaining fiber contacts a test sample. A compression device compresses the test sample. The compression device applies a time varying force to the test sample in which the force is sequentially increased. A polarimeter receives the light in a second polarization state and outputs polarization state data for the light in a second polarization state. Finally, a data processor is in communication with the polarimeter to receive and stores the polarization state data.

Abstract: An apparatus includes an all-optical transmission line having, at one wavelength, a pair of relatively orthogonal optical propagating modes whose local group velocities differ along a part of the all-optical transmission line. The all-optical transmission line is formed by a sequence of optically end-connected multi-mode fiber segments. The segments include, at least, 80% of the optical path length of the all-optical transmission line. Each segment is configured such that a differential group delay between the pair varies monotonically there along and changes by, at least, 200 pico-seconds thereon.

Abstract: An optical system is provided including a light source configured to emit a light; and a polarizing splitting multiplexing device including a first prism configured to split the light into two polarized light beams having different optical path lengths, and a second prism configured to combine the two polarized light beams. The first prism includes a first reflective surface and a first polarization splitting surface facing the first reflective surface, and the second prism includes a second reflective surface and a second polarization splitting surface facing the second reflective surface.

Abstract: Light is excited by a light source in a first waveguide mode. The light is converted to a second waveguide mode via a channel waveguide having a cross-sectional geometry normal to a direction of propagation of the light that rotates a polarity of the first waveguide mode to a second waveguide mode. The light in the second waveguide mode is delivered to a near-field transducer that provides electromagnetic heating for a heat assisted magnetic recording write head.

Abstract: A fast optical switch can be fabricated/constructed, when vanadium dioxide (VO2) ultra thin-film or a cluster of vanadium dioxide particles (less than 0.5 microns in diameter) embedded in an ultra thin-film of a polymeric material or in a mesh of metal nanowires is activated by either an electrical pulse (a voltage pulse or a current pulse) or a light pulse just to induce rapid insulator-to-metal phase transition (IMT) in vanadium dioxide ultra thin-film or vanadium dioxide particles embedded in an ultra thin-film of a polymeric material or in a mesh of metal nanowires. The applications of such a fast optical switch for an on-Demand optical add-drop subsystem, integrating with or without a wavelength converter are also described.

Abstract: Various particular embodiments include an optical structure, including: a photonic microring including an integral signal detector for detecting a level of an optical signal in the photonic microring; and a controller, coupled to the signal detector, for selectively adjusting a resonant frequency of the photonic microring based on the detected level of the optical signal in the photonic microring.

Abstract: The present invention discloses an elliptical cladding polarization-maintaining large-mode-area gain fiber, structurally comprising a core of the elliptical cladding polarization-maintaining large-mode-area gain fiber, an inner cladding, an elliptical stress layer, a first outer cladding, a second outer cladding and a third outer cladding, wherein the inner cladding surrounds the core; the elliptical stress layer surrounds the inner cladding, and has an elliptical cross-sectional shape; the first outer cladding surrounds the elliptical stress layer; the second outer cladding surrounds the first outer cladding; and the third outer cladding surrounds the second outer cladding. As the birefringence of the elliptical cladding polarization-maintaining fiber is directly proportional to the ellipticity and the deposition of a stress-applying area occurs during the preform rod forming process, procedures of preform drilling and the like are eliminated, and the likelihood of preform contamination is greatly reduced.

Abstract: A microphone array for detecting acoustic emissions generated by equipment. The array includes at least one grid having a plurality of sensors each including a compact arrangement of optical fiber having first and second optical fiber ends wherein the first optical fiber end of a first sensor is terminated. The array also includes an optoelectronic device coupled to a second optical fiber end of a second sensor, wherein the optoelectronic device generates laser light that is transmitted through the plurality of sensors in the grid and is reflected back to the optoelectronic device to enable detection of acoustic emissions.

Abstract: An electromagnetic wave resonator comprising a body, wherein the body: has a structure extending essentially in a plane (r, ?), comprises a material in a region between limit radii ri and ro, where 0?ri<ro and ro corresponds to a radius of a convex hull () of the structure; and allows for electromagnetic wave propagation, and wherein an effective refractive index ne(r), as obtained from angularly averaging a refractive index of the material in the plane (r, ?), decreases within said region.

Abstract: A system to fabricate hierarchical graded materials includes a reservoir to contain a material to be deposited, a print head connected to the reservoir to allow the print head to receive the material to be deposited, the print head having a mixing section, and an actuator connected to the print head, the actuator configured to actuate the print head in six axes of motion.

Abstract: A multi-channel transmitter optical subassembly (TOSA) with an off-center fiber in an optical coupling is disclosed, and can provide passive compensation for beam displacement introduced by optical isolators. The optical coupling receptacle can include an optical isolator configured to receive a focused light beam from a focus lens within the TOSA. The optical coupling receptacle may be offset such that a center line of the focused light beam entering the optical isolator is offset from a center line of a fiber within optical coupling receptacle. Thus the optical isolator receives the focused light beam from the focus lens and introduces beam displacement such that an optical signal is launched generally along a center line of the fiber. Thus the expected beam displacement introduced by the optical isolator is eliminated or otherwise mitigated by the offset between a center line of the fiber and a center position of the focus lens.

Abstract: Some embodiments of the disclosure relate to an optical transmission system that operates at a wavelength in the range from 950 nm to 1600 nm and that employs a single-mode optical transmitter and an optical receiver optically coupled to respective ends of a multimode fiber designed for 850 nm multimode operation. The optical transmission system also employs at least one single mode fiber situated within the optical pathway between the optical transmitter and the receiver and coupled to the multimode fiber.

Abstract: A photoelectric converter and a photoelectric connection device are provided. The photoelectric converter comprises a housing, wherein a driving controller, at least one information transmitting chip and at least one information receiving chip are provided on a substrate in the housing. The information transmitting chip, under the control of the driving controller, converts an electrical signal to be transmitted to an optical signal and transmits the optical signal through an optical fiber corresponding to the information transmitting chip. The information receiving chip, under the control of the driving controller, converts an external input optical signal that has reached a receiving surface of the information receiving chip to an electrical signal and outputs the electrical signal, wherein the external input optical signal is transmitted through an optical fiber corresponding to the information receiving chip.

Abstract: A polarization splitter/combiner and method of forming the same includes a first waveguide having a direction of propagation in a first direction. The height of the first waveguide is greater than the width of the first waveguide. A second waveguide is in proximity to the first waveguide and has a direction of propagation substantially parallel to the first direction in an interaction region. The second waveguide includes a first portion having a greater than the width of the first portion and a second portion having a width greater than a height of the second portion.

Abstract: A high harmonic optical generator comprising a laser arrangement for emitting a beam of polarized radiation at a fundamental frequency and an optical waveguide having a hollow core for a gaseous harmonic generation medium for the generation of high harmonics of the fundamental frequency, the optical waveguide having an optical propagation axis along the hollow core, the laser arrangement is configured to couple the beam of polarized radiation along the propagation axis of the hollow core optical waveguide to provide a beam of optical driving radiation for the high harmonic generation, the optical driving radiation having a plane of polarization that rotates about the propagation axis.

Abstract: The present invention includes novel techniques, apparatus, and systems for optical WDM communications. Tunable lasers are employed to generate respective subcarrier frequencies which represent subchannels of an ITU channel to which client signals can be mapped. In one embodiment, subchannels are polarization interleaved to reduce crosstalk. In another embodiment, polarization multiplexing is used to increase the spectral density. Client circuits can be divided and combined with one another before being mapped, independent of one another, to individual subchannels within and across ITU channels. A crosspoint switch can be used to control the client to subchannel mapping, thereby enabling subchannel protection switching and hitless wavelength switching.

Abstract: Methods and systems for hybrid integration of optical communication systems may comprise in an optical communication system comprising a silicon photonics die and one or more electronics die bonded to said silicon photonics die utilizing metal interconnects: receiving one or more continuous wave (CW) non-modulated optical signals in said silicon photonics die from an optical source external to said silicon photonics die; modulating said one or more received CW non-modulated optical signals in said silicon photonics die using electrical signals received from said one or more electronics die via said metal interconnects; receiving modulated optical signals in said silicon photonics die from one or more optical fibers coupled to said silicon photonics die; generating electrical signals in said silicon photonics die based on said received modulated optical signals; and communicating said generated electrical signals to at least one of said one or more electronics die via said metal interconnects.

Abstract: An all-fiber isolator as an optical isolator comprises: an optical fiber acting as an optical light guide for propagating incident light; and a Faraday rotator for rotating by 45° a plane of polarization polarized by the polarizer. The all-fiber isolator exhibits a magneto-optic effect enough to be used as an optical isolator at a visible light wavelength by including quantum dots in a core layer and/or an internal cladding layer of the optical fiber.

Abstract: There is provided a directional coupler including a first optical waveguide core and a second optical waveguide core that are arranged in separate and parallel to each other and that propagate one of TE polarized waves and TM polarized waves of an m-th order and propagate the other of the TE polarized waves and the TM polarized waves of an n-th order. A separation distance between the first optical waveguide core and the second optical waveguide core and a width of the first optical waveguide core and the second optical waveguide core are set such that a mode coupling coefficient of a p-th mode of one of the polarized waves and a mode coupling coefficient of a q-th mode of the other polarized waves match between the first optical waveguide core and the second optical waveguide core.

Abstract: In embodiments of a multiple waveguide imaging structure, a wearable display device includes left and right imaging units of respective display lens systems to generate an augmented reality image that includes a virtual image. Each of the left and right imaging units include a first waveguide for see-through viewing at a first field of view, where the first waveguide includes a first polarizing beam splitter to reflect light that enters at a first polarization orientation angle and pass through the light that enters at a second polarization orientation angle. Each of the left and right imaging units also include at least a second waveguide for see-through viewing at a second field of view, where the second waveguide includes a second polarizing beam splitter to reflect the light that enters at the first polarization orientation angle and pass through the light that enters at the second polarization orientation angle.

Abstract: A microlithography optical system includes a projection objective and an illumination system that includes a temperature compensated polarization-modulating optical element. The temperature compensated polarization-modulating optical element includes a first polarization-modulating optical element of optically active material, the first polarization-modulating optical element having a first specific rotation with a sign. The temperature compensated polarization-modulating optical element includes also includes a second polarization-modulating optical element of optically active material, the second polarization-modulating optical element having a second specific rotation with a sign opposite to the sign of the first specific rotation.

Abstract: An optical fiber ferrule has a plurality of guide holes therein for guiding a respective plurality of flat-sided fibers at an end of a multifiber optical fiber cable. The fibers' flat sides identify a particular rotational orientation of the fiber. Rotational alignment is achieved by urging the fibers' flat sides against a corresponding reference surface within the ferrule or within an alignment fixture. Also described is a fiber array block having a plurality of V-shaped grooves extending across an outer surface and terminating at an endface. The V-shaped grooves are shaped to guide a respective plurality of flat-sided fibers. A lid is installable across the plurality of V-shaped grooves, over fibers that have been loaded therein.

Abstract: An optical semiconductor device including: a substrate having a principal surface; first and second optical waveguides disposed on the principal surface of the substrate, the first and second optical waveguides extending in a first direction, the second optical waveguide being arranged adjacent to the first optical waveguide in a second direction intersecting with the first direction; first and second signal electrodes disposed on the first and second optical waveguides; a resistor disposed on the principal surface, the resistor being arranged between the first optical waveguide and the second optical waveguide, the resistor being electrically connected to the first signal electrode and the second signal electrode; a resin layer disposed on the principal surface, top surfaces of the first and second signal electrodes, and the resistor; and a capacitor disposed on the resin layer, the capacitor being electrically connected to the resistor through an opening of the resin layer.

Abstract: The present application is directed an optical gyroscope. The optical gyroscope includes a substrate including a first and a second waveguide disposed thereon. One or both of the waveguides may be doped with a rare-earth material. A crossing element is disposed between the first and the second waveguides to form a substantially orthogonal connection therebetween. The application is also directed to a system including an optical gyroscope. The application is further directed to a method of observing characteristics of the optical gyroscope.

Abstract: A high-order polarization conversion device configured of a planar optical waveguide, includes: a substrate; a lower clad disposed on the substrate; a core including a lower core and an upper core, the lower core being disposed on the lower clad and having a fixed height in a rectangular sectional shape, the upper core being formed of the same material as the lower core and having a fixed height in a rectangular sectional shape that is disposed continuously on the lower core; and an upper clad that is disposed on the core and the lower clad and is formed of the same material as the lower clad. The high-order polarization conversion device performs high-order polarization conversion between TE1 of the start portion and TM0 of the end portion.

Abstract: A compact polarization beam splitter is formed by cascading two stages of directional couplers each containing two waveguides laid in parallel with a coupling gap. Each waveguide is made by silicon nitride material having a minimum length configured to be comparable with a coupling length for a TE polarization mode being set as twice of a coupling length for a TM polarization mode. A first-stage direction coupler is optimized by making the coupling gap smaller/greater than a nominal value to maximize TE/TM extinction ratio at least for a shorter/longer wavelength window of a designated wavelength band and each of two second-stage directional couplers is optimized by making the coupling gap greater/smaller than the nominal value to maximize TE/TM extinction ratio at least for a complementary longer/shorter wavelength window of the same designated wavelength band.

Abstract: An optical receiver is disclosed. The optical receiver includes a polarization holding fiber configured to receive a light emitted from a light source and a polarizer configured to be irradiated with the light output from the polarization holding fiber. A method for adjusting the optical receiver comprises: inputting a plurality of lights having different wavelengths to a polarization holding fiber; detecting intensities of a plurality of lights output from the polarization holding fiber; calculating an adjustment value for an angle of the polarization holding fiber based on a ratio between the detected intensities of the plurality of lights; and adjusting the angle of the polarization holding fiber based on the calculated adjustment value.

Abstract: An optical fiber 10 propagates a light beam at a predetermined wavelength at least in an LP01 mode and an LP02 mode. In regions 11a and 11c in which the intensity of a light beam in the LP02 mode is greater than the intensity of a light beam in the LP01 mode, at least a part of a Young's modulus in the region 11c on the circumferential side of the region 11b in the core in which the intensity of the light beam in the LP01 mode is greater than the intensity of the light beam in the LP02 mode is smaller than a Young's modulus in the region 11b in which the intensity of the light beam in the LP01 mode is greater than the intensity of the light beam in the LP02 mode.

Abstract: The invention is a method and apparatus for creating mode division multiplexed channels capable of integration into photonic integrated circuits with direct spatial separation at the receiver end, thus removing the need for a DMUX module or at least significantly simplifying it. This is achieved by using a set of actuators that induce controllable mode mixing in a multi-mode fiber (MMF) at the transmitter in such a way that spatially separated channels are achieved at the receiver. As a result, no DMUX is required and failure of a single channel does not cause total communication link failure as occurs in links implemented with MUX/DMUX.

Abstract: A system, method, device, and apparatus provide a dielectric waveguide splitter/bi-directional link. A dielectric substrate fabricated into a first Y-junction waveguide with a first port splitting into a first branch leading to a second port and a second branch leading to a third port. An angle between the first branch and the second branch is below ninety degrees (90°). The dielectric waveguide splitter enables millimeter-wave (mmWave) transmission between the first port and the second port while reducing feedback of the mmWave between the second and third port. Two Y-junction waveguides may be fabricated back-to-back to provide simultaneous bidirectional mmWave transmission at a single frequency.

Abstract: A connector comprising an outer housing having a first keying element, an inner housing at least partially disposed in the outer housing and having second and third keying elements, the second keying element cooperating with the first keying element to align angularly the inner housing with the outer housing, a ferrule assembly at least partially disposed in the inner housing and having a ferrule and fourth and fifth keying elements, the fourth keying element cooperating with the third keying element to align angularly the ferrule assembly with the inner housing, an alignment member receiving at least a portion of the ferrule assembly, the alignment member having a sixth keying element to cooperate with the fifth keying element to align angularly the ferrule assembly with the alignment member, and wherein the clearance between the fifth and sixth keying elements is less than that between the first and second keying elements, and between the third and fourth keying elements.

Abstract: A microlithography optical system includes a projection objective and an illumination system that includes a temperature compensated polarization-modulating optical element. The temperature compensated polarization-modulating optical element includes a first polarization-modulating optical element of optically active material, the first polarization-modulating optical element having a first specific rotation with a sign. The temperature compensated polarization-modulating optical element includes also includes a second polarization-modulating optical element of optically active material, the second polarization-modulating optical element having a second specific rotation with a sign opposite to the sign of the first specific rotation.

Abstract: According to an aspect of an embodiment, a method of modeling an optical signal transmission path may include obtaining first transmission characteristics of an optical signal transmission path within an optical network based on a parameter of the optical network and randomly changing states of polarization of an optical signal within the optical signal transmission path. The method may also include obtaining second transmission characteristics of the optical signal transmission path based on the parameter and a first fixed state of polarization of the optical signal. The method may also include correlating the first transmission characteristics with the second transmission characteristics to obtain an effective state of polarization of the optical signal. A simulation of the optical signal transmission path based on the parameter and the effective state of polarization of the optical signal may produce transmission characteristics that may approximate the first transmission characteristics.

Abstract: An optical module connected to an optical fiber for transmitting light includes: a substrate; a ferrule that is formed from a material capable of transmitting therethrough light having a predetermined wavelength, accommodates an end of the optical fiber, and is fixed on the substrate with a fixing agent cured by being irradiated with the light capable of passing through the material; and a semiconductor chip that is disposed on the substrate and modulates light emitted from the end of the optical fiber accommodated in the ferrule.

Abstract: A system for estimating cross-phase modulation (XPM) impairments, wherein the method comprises: determining, according to a pump Jones matrix of a pump channel and a probe Jones matrix of a probe channel of each of fiber spans except for the first fiber span in a fiber transmission system, a polarization mode dispersion (PMD)-induced relative polarization status rotation matrix between channels of the each of fiber spans; and determining, according to the rotation matrix of the each of fiber spans, dispersion of a pump signal of the each of fiber spans, differential delay of the pump signal relative to a probe signal of the each of fiber spans and a gain of the each of fiber spans, polarization crosstalk and phase noise of the XPM impairments in the fiber transmission system. This allows the XPM impairments in the effect of the polarization mode dispersion to be quickly and accurately estimated.

Abstract: A pneumatic sensing apparatus for use in an overheat or fire alarm system comprising a sensing assembly that comprises a sensing means 51, 61, 71, containing a pressurized gas, coupled to a pressure sensor 52, 62, 72. The pressure sensor 52, 62, 72, is configured to produce a signal that is indicative of the gas pressure. The pressure sensor 52, 62, 72, comprises an optical pressure sensor and the signal comprises an optical signal.

Abstract: A multi-core transport system for a resonant fiber optic gyroscope is provided. The transport system has a transport fiber configured to transmit a clockwise signal and a counterclockwise signal, wherein the transport fiber has at least a first core and a second core. The first core and second core are configured such that when the first core imparts a first effect on the clockwise signal, the second core imparts a second effect on the counterclockwise signal, wherein the second effect substantially mirrors the first effect. The system further comprises a first coupler configured to optically couple the clockwise signal to the first core, and the counterclockwise signal to the second core; and a second coupler configured to optically couple the clockwise signal from the first core to a resonator, and the counterclockwise signal from the second core to the resonator.

Abstract: An apparatus includes a first waveguide configured to receive an input signal. A section of the first waveguide has a length between a first initial point and a first end point. A first polarization rotator is located within the section at a first distance from the first initial point of the section of the first waveguide. A section of a second waveguide is configured to receive the input signal, and has the same length between the second initial point and a second end point. A second polarization rotator is located within the section of the second waveguide at a second distance from the second initial point of the section of the second waveguide. More particularly, a relative distance between the first distance and the second distance is configured to achieve a desired phase delay of an output signal from the first waveguide and an output signal from the second waveguide.

Abstract: A polarization mode dispersion (PMD) generating apparatus includes a polarization plane controller; a unit function block including a first differential group delay (DGD) generator, a first mode mixer, and a second DGD generator, a second mode mixer and a reflective mirror, which are arranged in this order from the input side of input light free from PMD. Part of the first and second DGD generators is disposed on a driven stage to modify the optical path length. The input light has polarization converted by the polarization plane controller and is inputted to the first DGD generator to propagate back and forth on an optical path from the unit function block through the second mode mixer to the reflective mirror. In the PMD-generating apparatus, the driven stage adjusts a DGD amount between orthogonal eigen-polarization modes generated in the first and second DGD generators on the basis of an applicable wavelength band.

Abstract: The present disclosure provides systems and methods for avoiding beam obstructions during inscription of fiber gratings. For some embodiments, an optical fiber is re-oriented during fiber inscription to avoid obstruction of the actinic beam.

Abstract: Mode expander isolator for a fiber laser amplifier comprising an optical fiber input, an optical fiber output, an isolator and at least one lens, the optical fiber input for coupling a first optical fiber with the mode expander isolator, the optical fiber output for coupling a second optical fiber with the mode expander isolator, the isolator being positioned between the optical fiber input and the optical fiber output for preventing back-reflected laser light from reaching the optical fiber input and wherein the isolator and the at least one lens form a free space mode expander.

Abstract: The present invention discloses a 3D polarization beam splitter based on 2D photonic crystal slabs which comprises a 2D photonic crystal slab positioned at the top part, a 2D photonic crystal slab positioned at the bottom part and perpendicular to the top 2D photonic crystal slab, and an input coupling dielectric block; a P polarization wave output waveguide is positioned in the top 2D photonic crystal slab; an S polarization wave output waveguide is positioned in the bottom 2D photonic crystal slab; the output port of the P polarization wave output waveguide and the output port of the S polarization wave output waveguide are apart from each other in 3D space; the photonic crystal slabs include a background dielectric material and dielectric rods.

Abstract: A light source assembly (300) for emitting depolarized light, and comprising: at least one light source (312) configured to emit substantially polarized light; and a light depolarizer (318) arranged to receive light from the light source and comprising a high birefringence optical fiber having a longitudinal core and orthogonal birefringent axes having an angular displacement around the core that varies along the length of the fiber, wherein light emitted from the depolarizer comprises a plurality of polarization states.