Abstract: An optical circuit includes one or more input waveguides, a plurality of output waveguides, and a reflector structure. At least a portion of the reflector structure forms an interface with the one or more input waveguides. The portion of the reflector structure has a smaller refractive index than the one or more input waveguides. An electrical circuit is electrically coupled to the optical circuit. The electrical circuit generates and sends different electrical signals to the reflector structure. In response to the reflector structure receiving the different electrical signals, a carrier concentration level at or near the interface or a temperature at or near the interface changes, such that incident radiation received from the one or more input waveguides is tunably reflected by the reflector structure into a targeted output waveguide of the plurality of output waveguides.

Abstract: A photonic polarization splitter rotator (PSR) includes a substrate, a first optical waveguide disposed on the substrate at a first layer, the first optical waveguide having a substantially rectangular shape and longitudinally arranged between a first end of the first optical waveguide and a second end of the first optical waveguide, and a second optical waveguide arranged to have a partial and fixed amount of overlap over a predetermined length of the first optical waveguide.

Abstract: A first portion of incoming light and a second portion of incoming light travel in opposite directions within a first optical waveguide. A ring resonator in-couples the first portion of incoming light and the second portion of incoming light from the first optical waveguide, such that the first portion of incoming light and the second portion of incoming light travel in opposite directions within the ring resonator. A second optical waveguide is disposed to in-couple the first portion of incoming light and the second portion of incoming light couple from the ring resonator, such that the first portion of incoming light and the second portion of incoming light travel in opposite directions within the second optical waveguide away from the ring resonator. One or more photodetector(s) are optically connected to receive the first portion of incoming light and the second portion of incoming light from the second optical waveguide.

Abstract: Disclosed are an optical module, an optical communication device and an optical transmission system. The optical module includes a housing; a main board where are arrange a first transmitting unit and a first receiving unit; a first optical circulator, a first port of which is connected to an output end of the first transmitting unit, and a third port of which is connected to an input end of the first receiving unit; and a first optical fiber adapter connected to a second port of the first optical circulator, wherein an optical signal from the output end of the first transmitting unit is transmitted to the second port along the first port of the first optical circulator; and the first optical fiber adapter receives an optical signal input from outside, and transmits it to the third port along the second port of the first optical circulator.

Abstract: A light detection and ranging (LiDAR) system includes a first optical source and a second optical source configured to emit respectively a first optical beam and a second optical beam that have opposite polarizations. The LiDAR system further includes a beam combining component to combine the first optical beam and the second optical beam into a single spatial mode optical beam and a first beam splitting component to split the single spatial mode optical beam into a plurality of single spatial mode optical beams.

Abstract: A nonreciprocal waveguide includes a substrate, a light propagation path, a magnetic member, an insulating layer, and a mask. The light propagation path is positioned at the substrate along a substrate surface. The magnetic member is positioned at the substrate along part of the light propagation path in a longitudinal direction. The insulating layer is positioned at the substrate and contains the light propagation path and the magnetic member. Inside the insulating layer, the mask is positioned further away than the light propagation path from the substrate. As seen from a direction perpendicular to the substrate surface, the mask overlaps at least part of the light propagation path in a width direction from a side of the light propagation path opposite to the magnetic member in the width direction. The mask is positioned in at least a range in which the magnetic member is positioned in the longitudinal direction.

Abstract: A measurement system is proposed for building a magnetic field map of an object. The system comprising: a light source arrangement for emitting a plurality of light beams, a respective light beam being configured to travel in the measurement system along a respective optical path; a plurality of measurement sensors sharing a first magneto-optical layer comprising at least a first Faraday material layer and a first light reflector for reflecting the plurality of light beams travelled through the first Faraday material layer in a first direction back to the first Faraday material layer in a second, opposite direction; one or more reference sensors; and one or more light detectors.

Abstract: The invention relates to a spliced optical fiber comprising a first and second polarization-maintaining optical fiber connected at ends by splicing; to fiber optic current sensors; and to a method for protecting the spliced optical fiber against mechanical stress and/or humidity. A protection tube is arranged around the spliced optical fiber in a splice section of the spliced optical fiber. A first and second end of the protection tube is sealed to the spliced optical fiber by first and second sealing arrangement for protecting the splice.

Abstract: An optical device is provided. The optical device includes a substrate, a first optical layer; a high k layer, and a second optical layer. The first optical layer is disposed on the substrate. The first optical layer comprises a top surface, a first sidewall, and a second side-wall opposite thereto. The high k layer is disposed on the top surface of the first optical layer. The second optical layer is disposed on the high k layer. The second optical layer includes a top surface, a third sidewall, and a fourth sidewall opposite thereto. The first sidewall of the first optical layer is misaligned with the third sidewall of the second optical layer. The second sidewall of the first optical layer is coplanar with the fourth sidewall of the second optical layer.

Abstract: An optical device including: a substrate; an optical waveguide formed at the substrate; and a protective layer formed adjacent to the optical waveguide, wherein the optical waveguide includes multiple side surfaces that intersect the substrate, at least one side surface of the optical waveguide is provided with a rough surface. According to the optical device of the present invention, the light propagation loss can be reduced.

Abstract: A polarization splitter-rotator (PSR) is described. The PSR having a silicon nitride based waveguide to split and rotate an optical beam. The silicon nitride based waveguide having a first silicon nitride segment including a first layer and a second layer coupled with the first layer.

Abstract: The present disclosure relates to a connector assembly and a corresponding method to reverse polarity of the connector. The method enables polarity reversal without bending/twisting optical fibers within the connector assembly.

Abstract: An isolator includes a first core, a second core, a nonreciprocal member, and a magnetic body. The first core and the second core extend in a first direction and are positioned side by side with a cladding therebetween in a second direction that intersects the first direction. The nonreciprocal member is in contact with at least a part of the second core while being positioned side by side with the second core in the second direction. In a magnetic field generated by the magnetic body in a portion where the nonreciprocal member is positioned, a component in a third direction perpendicular to the first direction and the second direction is greater than any component other than the component in the third direction.

Abstract: An optical waveguide-transmitter apparatus, an ultrasonic transceiver apparatus, an ultrasonic imaging apparatus and an associated production method are disclosed. The optical waveguide-transmitter apparatus includes a substrate made of a semiconductor material; a carrier layer arranged on the substrate; and at least one transmitter-optical waveguide made of a semiconductor material with a refractive index greater than a refractive index of the carrier layer. At least one side of the waveguide is at least partially surrounded by the carrier layer. The waveguide is configured at an end facing toward the examination region for a decoupling of the light beams into the examination region for generating the ultrasonic waves in the examination region by way of the decoupled light beams for an optoacoustic imaging and/or has, on the end facing toward the examination region, an optical absorption layer for such a conversion of the light beams.

Abstract: A compact, portable Raman spectrometer makes fast, sensitive standoff measurements at little to no risk of eye injury or igniting the materials being probed. This spectrometer uses differential Raman spectroscopy and ambient light measurements to measure point-and-shoot Raman signatures of dark or highly fluorescent materials at distances of 1 cm to 10 m or more. It scans the Raman pump beam(s) across the sample to reduce the risk of unduly heating or igniting the sample. Beam scanning also transforms the spectrometer into an instrument with a lower effective safety classification, reducing the risk of eye injury. The spectrometer's long standoff range automatic focusing make it easier to identify chemicals through clear and translucent obstacles, such as flow tubes, windows, and containers. And the spectrometer's components are light and small enough to be packaged in a handheld housing or housing suitable for a small robot to carry.

Abstract: Aspects of the present disclosure describe systems, methods. and structures directed to an integrated 3-way branching unit switch module suitable for undersea application.

Abstract: Systems and methods are provided for determining a polarization state of an input RF signal. Two distinct RF antennas receive the input RF signal and output a first antenna signal and a second antenna signal. Polarizsations of the first and second antenna signals are orthogonal to one another. The first antenna signal is converted to a first optical signal, and the first optical signal is passed through a first optical signal to introduce a first delay. The delayed first optical signal is converted to a first RF signal. An amplitude ratio and a phase difference are determined between the first RF signal and a second RF signal that is associated with the second antenna and optionally includes a second delay. A polarization angle or polarization type of the input RF signal is determined based on the amplitude ratio and phase difference of the first and second RF signals.

Abstract: Integrated passive/active modulator units, integrated passive/active modulators comprising one or more units, and corresponding methods of fabrication and use are provided. In an example embodiment, a unit comprises an upstream passive portion comprising a passive waveguide; a downstream passive portion comprising a continuation of the passive waveguide; and an active portion between the upstream passive portion and the downstream passive portion. The active portion comprises an active waveguide and electrical contacts in electrical communication with the active waveguide. The active waveguide comprises an upstream taper and/or a downstream taper. The upstream taper is configured to optically couple the active waveguide to the passive waveguide of the upstream portion and the downstream taper is configured to optically couple the active waveguide to the continuation of the passive waveguide of the downstream portion.

Abstract: An apparatus and method for displaying an image are disclosed. The apparatus includes microLED unit cells including sets of microLEDs each emitting light and at least one lens to control an emission angle and emission profile of the light emitted by the microLED unit cells. A display controller controls an intensity distribution of the microLED unit cells in accordance with first and second video data signals such that a first portion of the emitted light is emitted at a first emission angle with a first emission profile at a first observation angle relative to a display and a second portion of the emitted light is emitted at a second emission angle with a second emission profile at a second observation angle relative to the display. The first and second light portions form unrelated images.

Abstract: A mode multiplexing/demultiplexing optical circuit with a reduced inter-mode crosstalk is provided. A mode multiplexing/demultiplexing optical circuit includes a Port 1 through which light from a light source is input to a waveguide, a Port 3 through which light propagating through a first waveguide is output, a mode conversion unit located adjacent to the first waveguide, and configured to convert a first-order mode light input from the Port 3 to a second-order mode, and Port 2 configured to convert, via a waveguide located adjacent to the mode conversion unit, second-order mode light input to the mode conversion unit to a zeroth-order mode.

Abstract: An optical detection device and method for detecting temperature changes and/or wavelength changes of an optical probe signal includes transmitting an optical probe signal having a predetermined wavelength to an optical input port of an optical waveguide; detecting first and second optical detection signal at first and second optical output ports via first and second opto-electrical converters which create corresponding first and second electrical signals; measuring values of the first and second electrical signal and determining an absolute temperature or a temperature change of the optical waveguide and/or an absolute wavelength value or a wavelength change of the optical probe signal via values measured of the first and second electrical signals and first and second previously determined wavelengths and temperature dependencies of both first and second power transfer functions.

Abstract: Structures including an optical component and methods of fabricating a structure including an optical component. The structure includes a substrate, an optical component including a waveguide core, and a back-end-of-line stack including a heat spreader layer. The optical component is positioned in a vertical direction between the substrate and the back-end-of-line stack. The waveguide core contains a first material having a first thermal conductivity, and the heat spreader layer contains a second material having a second thermal conductivity that is greater than the first thermal conductivity of the first material.

Abstract: The present disclosure is related to transmitting and receiving media channels, such as audio and video channels. These channels may be transmitted as packets from one or more transmitting devices to one or more receiving devices for playout. Certain embodiments of the present disclosure include systems, methods, and computer-readable media for determining latency of a data network for synchronised playout of received signals. Additionally, certain embodiments of the present disclosure include systems, methods, and computer-readable media for synchronising playout among devices connected to a data network.

Abstract: A system can include an optical receiver. The optical receiver can have an optical delay component and at least one electrical component (e.g., diode, resistor and/or transistor) operatively coupled to (e.g., integrated within) the optical delay component. The system can further include a processing device, operatively coupled to a memory, that can tune an amount of optical delay implemented by the optical delay component in a low loss and/or low dispersion manner. For example, the processing device can adjust, based on optical delay tuning data (e.g., built-in self-test (BIST) data), the at least one electrical component to modify at least one property of the at least one optical delay component.

Abstract: Provided are a light detection and ranging (LiDAR) device and a method using the same. The LiDAR device includes a light scanner configured to periodically scan a region in a surrounding area by sequentially changing a traveling path of incident light; a first light source configured to provide a first light to the light scanner in a first incidence direction; and a second light source configured to provide a second light to the light scanner in a second incidence direction different from the first incidence direction.

Abstract: A method of rotating polarization of light travelling in a waveguide includes receiving an optical signal having a first polarization state at a first section of the waveguide, the first section of the waveguide being disposed on a plane of a substrate, using a micro-electromechanical system (MEMS) device, angling a second section of the waveguide out of the plane of the substrate, and outputting the optical signal with a second polarization state, different from the first polarization state, on a third section of the waveguide, the third section of the waveguide also being disposed on the plane of the substrate. A control loop is provided to sense the polarization shift to control the angle of the MEMS device to compensate for that shift.

Abstract: Provided are an apparatus and method of generating a terahertz (THz) signal using a directly-modulated laser. An apparatus of generating a THz signal includes a first directly-modulated laser configured to output a local oscillator (LO) signal, a second directly-modulated laser configured to receive a baseband signal used as data and optically modulate the baseband signal, a band-pass filter configured to filter a spectral component of the baseband signal optically modulated and outputted through the second directly-modulated laser by using a specific frequency bandwidth, a coupler configured to couple the baseband signal filtered through the band-pass filter and the LO signal to each other, and a uni-travelling-carrier photodiode (UTC-PD) configured to generate a THz signal by beating the baseband signal and the LO signal coupled to each other.

Abstract: An interferometer includes a coherent light source and an array of electrically coupled light-sensitive pixel elements. The interferometer is configured to direct an internal optical path of the coherent light source and an external optical path of the coherent light source into a monolithic unit cell. In addition, the monolithic unit cell is configured to direct the internal optical path first through the monolithic unit cell and then onto the array and also configured to direct the external optical path back outside the monolithic unit cell through an external environment and then back into the monolithic unit cell and finally onto the array. In addition, interferometer is further configured to combine the internal optical path and the external optical path at the array and produce a first interferogram on the array, the interferogram characterizing an optical property of the external environment.

Abstract: A polarization scrambler using a retardance element (RE) is disclosed. The polarization scrambler may include an optical fiber input to transmit an optical signal, and a beam expander to receive and expand the optical signal to create an expanded optical signal. The polarization scrambler may include a retardance element (RE) to cause a polarization scrambling effect on the expanded optical signal and to create a scrambled expanded optical signal. The polarization scrambler may include a beam reducer to receive and reduce the scrambled expanded optical signal to create a scrambled optical signal. The polarization to scrambler may include an optical fiber output to receive scrambled optical signal. The optical fiber output may transmit the scrambled optical signal to one or more downstream optical components.

Abstract: A nonlinear fiber interferometer is disclosed suitable for fiber sensor and other applications. A first nonlinear fiber section amplifies probe and conjugate sidebands of a pump through four-wave mixing. A second section introduces a phase shift to be measured, for example from a sensor. A third nonlinear fiber section amplifies with phase-sensitive gain to increase signal-to-noise ratio. Based on phase-sensitive output power of probe and/or conjugate components, the phase shift can be measured. Superior performance can be obtained by balancing gain between the (first and third) nonlinear sections. Non-fiber, for example photonic integrated circuit, embodiments are disclosed. Differential sensing, alternative detection schemes, sensing applications, associated methods, and other variations are disclosed.

Abstract: Device cost and electric power consumption are reduced. Nodes 11a to 11d as optical add/drop multiplexers each include cAWGs 24a and 24b that include a plurality of first side ports and a plurality of second side ports connected between light transmission paths as optical fibers 12 and 13 and transponders 25a to 25n and in which a first optical signal input-output channel interval of each port is a plurality of times larger than a second optical signal input-output channel interval of ports of the transponders 25a to 25n and optical signals of a plurality of different wavelengths from one or a plurality of transponders 25a to 25n or the light transmission paths can pass through a first channel. The cAWGs 24a and 24b cause the optical signals from the transponders 25a to 25n to pass through the first side ports, and then cyclically outputs and transmits the optical signals through the plurality of second side ports in a predetermined order to the light transmission paths.

Abstract: A terahertz polarization beam splitter based on a two-core negative curvature fiber is provided, which relates to the technical field of optical fiber communication. The polarization beam splitter includes: a base circular tube and core separation structures. Multiple large cladding tubes are internally tangent and connected to an inner wall of the base circular tube and arranged at equal intervals along a circumference of the inner wall of the base circular tube, and the multiple large cladding tubes are symmetrically distributed on the inner wall of the base circular tube. Embedded circular tubes are internally tangent and connected to inner walls of the multiple large cladding tubes respectively. The core separation structures are two in number.

Abstract: An optical circuit element formed on a substrate, the optical circuit element includes a first waveguide and a second waveguide, the second waveguide having a shape in a width direction, the shape being asymmetrical to the first waveguide. The first waveguide includes a first segment and a second segment, the first segment having a width that changes along a light propagation direction, the second segment continuous with the first segment. The second waveguide includes a coupled waveguide adjacent to the second segment of the first waveguide. At least one of the second segment and the coupled waveguide has a shape with a width that changes along the light propagation direction.

Abstract: An optical device includes: a ground electrode having a ground potential; a thin film optical waveguide formed by a thin film substrate stacked on the ground electrode; a signal electrode that is arranged at a position facing the ground electrode across the thin film optical waveguide and that transmits a high frequency signal; and a dielectric that covers at least a part of an exposed surface of the signal electrode.

Abstract: The present disclosure provides an optical display system and method, and a display device. The optical display system includes: a display screen; a light split member configured to split light from the display screen into a first polarized light and a second polarized light with different polarization directions; a first optical waveguide configured to guide the first polarized light to a light exit side of the optical display system; and a second optical waveguide located at a light exit side of the first optical waveguide, spaced apart from the first optical waveguide, and configured to at least partially transmit the first polarized light and guide the second polarized light to the light exit side of the optical display system.

Abstract: Various forms of optical circulator are disclosed. The optical circulators act on polarisation of the light to direct light between its ports. Also disclosed are systems and methods for facilitating estimation of a spatial profile of an environment based on a light detection and ranging (LiDAR) based technique. The systems and method may include or use one or more of the various forms of optical circulator. In one arrangement, the present disclosure facilitates spatial profile estimation based on directing light over one dimension, such as along the vertical direction. In another arrangement, by further directing the one-dimensionally directed light in another dimension, such as along the horizontal direction, the present disclosure facilitates spatial profile estimation based on directing light in two dimensions.

Abstract: A first waveguide and a second waveguide including a first layer and a second layer are provided. In a first longitudinal segment, the first layer gradually approaches a first waveguide in a first transverse direction. In a second longitudinal segment, the first and second waveguides are longitudinally oriented. In a third longitudinal segment, the first layer includes a length portion having a width in the first transverse direction that gradually decreases along the third longitudinal segment, and the second layer includes a length portion having a width in the first transverse direction that gradually increases along the third longitudinal segment.

Abstract: A Mach-Zehnder interferometer (MZI) filter comprising one or more passive compensation structures are described. The passive compensation structures yield MZI filters that are intrinsically tolerant to perturbations in waveguide dimensions and/or other ambient conditions. The use of n+1 waveguide widths can mitigate n different sources of perturbation to the filter. The use of at least three different waveguide widths for each Mach-Zehnder waveguide can alleviate sensitivity of filter performance to random width or temperature variations. A tolerance compensation portion is positioned between a first coupler section and a second coupler section, wherein the tolerance compensation portion includes a first compensation section having a second width, a second compensation section having a third width and a third compensation section having a fourth width, wherein the fourth width is greater than the third width and the third width is greater than the second width.

Abstract: A single-ended output circulator includes a three-core optical fiber head having first, second, and third optical fiber cores; a walk-off crystal having a first surface facing towards the second end of the three-core optical fiber head tube and a second surface facing away from the second end of the three-core optical fiber head tube; a plurality of half-wave plates each having a first surface coupled to the second surface of the walk-off crystal and a second surface facing away from the second surface of the walk-off crystal; a collimating lens having a first end and a second end; a reflection mirror configured to reflect light beams from the collimating lens; an optical prism between the collimating lens and the reflection mirror and configured to transmit a light beam along a propagation direction according to a polarization direction of the light beam; and a polarization rotator.

Abstract: A photonic polarization splitter rotator (PSR) includes a substrate, a first optical waveguide disposed in the substrate on a first layer, the first optical waveguide having a curved portion between a first end of the first optical waveguide and a second end of the first optical waveguide, and a second optical waveguide disposed in the substrate on a second layer, above the first layer, the second optical waveguide having a substantially rectangular shape and longitudinally arranged between the first end of the first optical waveguide and the second end of the first optical waveguide.

Abstract: A Faraday rotator and an optical isolator having a high transmittance and a high Verdet constant are provided. The optical isolator includes at least a Faraday rotator that rotates a polarization plane of incident light in a non-reciprocal manner, a polarizer disposed on a light incident side of the Faraday rotator, and an analyzer disposed on a light exit side of the Faraday rotator. The Faraday rotator is made of an oxide containing ytterbium oxide (Yb2O3), and is manufactured by a ceramic manufacturing process, wherein the oxide is allowed to contain an oxide of a metal other than ytterbium, and the proportion of ytterbium in all metal atoms in the oxide is 80% or more.

Abstract: The present disclosure provides a liquid crystal phase shifter array, a driving method thereof, and a laser scanner. The liquid crystal phase shifter array includes a plurality of liquid crystal phase shifter units arranged in array, a first substrate and a second substrate disposed opposite to each other, a liquid crystal layer provided between the first substrate and the second substrate, a first electrode provided on the first substrate, and a second electrode provided on the second substrate. Each liquid crystal phase shifter unit includes a first optical waveguide provided on a side of the first substrate proximal to the liquid crystal layer and arranged to be in direct contact with the liquid crystal layer.

Abstract: Disclosed herein are techniques for improving the light collection efficiency in coaxial LiDAR systems. A coaxial LiDAR system includes a photodetector, a first polarization beam splitter configured to receive a returned light beam including a first linear polarization component and a second linear polarization component and direct the different linear polarization components to different respective directions, a polarization beam combiner configured to transmit the first linear polarization component from the first polarization beam splitter to the photodetector, a non-reciprocal polarization rotator configured to transmit the second linear polarization component from the first polarization beam splitter, and a second polarization beam splitter configured to reflect the second linear polarization component from the non-reciprocal polarization rotator towards the polarization beam combiner.

Abstract: Disclosed herein is an optical filter configured for wavelength division and multiplexing capable of transmitting and receiving signals. The optical filter includes an optical waveguide configured to receive at an input multiple signals with different wavelengths. The optical filter includes a plurality of channels coupled at different locations along a length of the optical waveguide. Each of the plurality of channels is configured to transmit a respective one of the multiple signals. A number of ring filter stages in a first channel of the plurality of channels that is closer to the input of the optical waveguide is greater than a second channel in the plurality of channels further away from the input of the optical waveguide.

Abstract: An optical waveguide device includes first and second waveguides formed parallel to each other. The first waveguide includes a first rib and a first slab. The first slab is formed in a region between the first rib and the second waveguide. The second waveguide includes a second rib, a second slab and a third slab. The second rib is provided between the second slab and the third slab. The first and second slabs are integrally formed. At one end of the optical waveguide device, a first effective refractive index that indicates an effective refractive index of a TEi mode in the first waveguide is higher than a second effective refractive index that indicates an effective refractive index of a TEj mode in the second waveguide. At another end, the first effective refractive index is lower than the second effective refractive index.

Abstract: A semiconductor laser shaping device includes, along the light path of a semiconductor laser, a fast axis collimating lens, slow axis collimating lens, the half wave plate, a polarization beam combining prism, and a crawling prism group. The laser emitted by the semiconductor laser is collimated by a fast-axis collimating lens and then by a slow-axis collimating lens, and subsequently injected into a half wave plate and polarization beam combining prism, which compresses its spot size along the slow axis while keeping the spot size unchanged along the fast axis. The laser beam then passes through the crawling prism group, which shifts a portion of the light in the slow-axis direction to the fast-axis direction, which again compresses the light beam in the slow-axis direction. The device can reduce the beam size of a semiconductor laser in the slow-axis direction, reducing its beam parameter product and improving beam quality.

Abstract: An anti-torsion solid-core polarization-maintaining photonic crystal fiber includes a cladding having an inner layer arranged around the core and an outer layer between the inner layer and the outer wall of the cladding. The inner layer has multi-layer air holes used to construct optical properties and two micron-size air holes arranged along the x-axis extending in the center producing form birefringence. The outer layer includes multi-layer air holes arranged radially along the y-axis. The size and arrangement of the multi-layer air holes in the outer layer cause the bending stiffness of the photonic crystal fiber along the x-axis to be different from that along the y-axis. While meeting the requirements of the optical properties of the fiber, the photonic crystal fiber possesses an anti-torsion ability due to the anisotropy of stress distribution in the radial direction, thereby reducing the non-reciprocal phase difference generated by the magneto-optic Faraday Effect.

Abstract: A polarization recovery device comprises an input that receives a first optical signal with unknown polarization and with at least one signal parameter at an initial value, a first output that outputs a second optical signal with known polarization and with the at least one signal parameter at or near the initial value, and a recovery block that generates the second optical signal based on the first optical signal.

Abstract: The present invention discloses a directional photonic coupler (1) with independent tuning of the coupling factor and phase difference. The coupler comprises: two waveguides (4, 5), with respective propagation constants “?1, ?2”, on which phase shifters (6, 7) configured to modify the propagation coefficients are located. Both phase shifters are configured such that, by independent modification (differential or unique) of the propagation coefficients, the power coupling factor (K) between an input signal (2a or 2b) and the output signals (3b and 3a) is tuned, and by equal and simultaneous modification of the propagation coefficients, the common phase difference of the optical output signals (3 a, 3b) is tuned. A third phase shifter (15) can be used to retune the phase difference at the input/output of one of the waveguides. The coupler is of particular interest in PIC circuits, coupled resonators, Mach-Zehnder interferometers and mesh structures.

Abstract: A broadband radiation source device, including a fiber assembly having a plurality of optical fibers, each optical fiber being filled with a gas medium, wherein the broadband radiation source device is operable such that subsets of the optical fibers are independently selectable for receiving a beam of input radiation so as to generate a broadband output from only a subset of the plurality of optical fibers at any one time.