Abstract: Systems, methods, and devices are disclosed for implementing photonic links. Methods include transmitting light using an optical emitter, splitting, using an input coupler, the light into a first path and a second path, the first path being provided to a modulator, and the second path being provided to a phase shifter, and combining, using an output coupler, an output of the modulator and an output of the phase shifter. Methods further include identifying a modulator phase angle that reduces a third order distortion at an output of the output coupler, applying a first bias voltage to a modulator to maintain the identified modulator phase angle, and applying a control signal to the phase shifter to maintain a phase difference between an output of the modulator and an output of a phase shifter.

Abstract: A high average and peak power single transverse mode laser system is operative to output ultrashort single mode (SM) pulses in femtosecond-, picosecond- or nanosecond-pulse duration range at a kW to MW peak power level. The disclosed system deploys master oscillator power amplifier configuration (MOPA) including a SM fiber seed, outputting a pulsed signal beam at or near 1030 nm wavelength, and a Yb crystal booster. The booster is end-pumped by a pump beam output from a SM or low-mode CW fiber laser at a pump wavelength in a 1000-1020 nm wavelength range so that the signal and pump wavelengths are selected to have an ultra-low-quantum defect of less than 3%.

Abstract: A photonic processor includes a modulator, an optical filter, and a polarization combiner. The modulator is configured to receive an electronic signal, first optical control signal, and first optical operating signal, the first optical operating signal received from an optical source circuit on a first path having a first length, the first optical control signal received from an optical control circuit on the first path; modulate the first optical operating signal using the electronic signal to provide an intensity-modulated optical operating signal comprising a first optical operating carrier, first sideband, and second sideband; and modulate the first optical control signal using the electronic signal to provide an intensity-modulated control signal comprising a first optical control carrier. The optical filter is configured to extract the first optical operating carrier and first sideband from the intensity-modulated optical operating signal and provide the second sideband and the control carrier.

Abstract: Described herein are optical sensing devices for photonic integrated circuits (PICs). A PIC may comprise a plurality of waveguides formed in a silicon on insulator (SOI) substrate, and a plurality of heterogeneous lasers, each laser formed from a silicon material of the SOI substrate and to emit an output wavelength comprising an infrared wavelength. Each of these lasers may comprise a resonant cavity included in one of the plurality of waveguides, and a gain material comprising a non-silicon material and adiabatically coupled to the respective waveguide. A light directing element may direct outputs of the plurality of heterogeneous lasers from the PIC towards an object, and one or more detectors may detect light from the plurality of heterogeneous lasers reflected from or transmitted through the object.

Abstract: Devices, methods and systems for generating wideband, high-fidelity arbitrary radio frequency (RF) passband signals are described. A voltage tunable optical filter for arbitrary RF passband signal generation includes a first input configured to receive a broadband optical pulse train, a second input configured to receive a first control voltage representative of an amplitude signal, an electrooptic modulator to receive the broadband optical pulse train and the first control voltage, to modulate the broadband optical pulse train in accordance with the amplitude signal, and to produce two complementary optical outputs that form two arms of an interferometer, an optical delay component to impart an optical path difference into one of the complementary outputs of the electrooptic modulator, and a combiner or a splitter to receive two complementary optical outputs of the electrooptic modulator after impartation of the optical path difference and to produce an output interference pattern of fringes.

Abstract: An optical wireless communication system comprising a transmitter apparatus that comprises: an illumination light source configured to output visible light for illumination purposes, and a controller configured to control operation of the illumination light source to produce modulation of the visible light to provide an optical wireless communication signal representing data; a further light source configured to output further light, wherein the controller is configured to control operation of the further light source to produce modulation of the further light to provide a further optical wireless communication signal representing substantially the same data, wherein the visible light and the further light have different wavelengths.

Abstract: A method and structure for probabilistic shaping and compensation techniques in coherent optical receivers. According to an example, the present invention provides a method and structure for an implementation of distribution matcher encoders and decoders for probabilistic shaping applications. The techniques involved avoid the traditional implementations based on arithmetic coding, which requires intensive multiplication functions. Furthermore, these probabilistic shaping techniques can be used in combination with LDPC codes through reverse concatenation techniques.

Abstract: A narrow-linewidth tunable external cavity laser includes, sequentially arranged along an optical path, a laser gain chip, a collimating lens, a bandpass filter, a tunable filter, and an output cavity surface. The laser gain chip includes a first end surface and a second end surface positioned along the optical path. The first end surface is further away from the collimating lens and is coated with a highly reflective film to form an external cavity with the output cavity surface.

Abstract: Systems and methods for communicating using both radio frequency (RF) communication and light communication (LC) are disclosed. An example device comprises radio frequency communication circuitry, a light communication transmitter; a light communication receiver; a processor for controlling the device according to executable code; and memory for storing data and executable code, wherein the executable code comprises instructions for causing the processor to establish RF communication with an RF access point using the RF communication circuitry; and to establish LC communication with an LC access point using the LC transmitter, the LC receiver, or both.

Abstract: The disclosure relates to a multi-modulation-format compatible high-speed laser signal generation system and method. The disclosure can greatly improve modulation format compatibility of a laser communication system and saves system upgrading costs and resource costs. The system mainly includes a control instruction unit, a serial-parallel changeover switch unit, a precoding switch unit, a power control unit, an IQ modulator, a narrow line width laser, and a bias point control unit, wherein the control instruction unit is respectively connected to the serial-parallel changeover switch unit, the precoding switch unit, the power control unit, and the bias point control unit; the serial-parallel changeover switch unit, the precoding switch unit, the power control unit, and the IQ modulator are electrically connected in sequence; the narrow line width laser is connected to an optical input end of the IQ modulator; and the bias point control unit is connected to the IQ modulator.

Abstract: A light-transmitting subsystem can include an LED light source including a first to LED light to emit a first wavelength of light with a first center-emission wavelength and a second LED light to emit a second wavelength of light with a second center-emission wavelength that is offset from the first center-emission wavelength. The system can include a first reference oscillator to receive a reference signal from a remote or broadcasting source, and can also include a synchronous modulation and power system to convert the reference signal from a synchronous relative high frequency signal to a synchronous relative low frequency signal and provide synchronized power pulses to the first LED light and the second LED light in synchronous correlation with the synchronous relative low frequency signal to generate a stream of modulated light-signal pulses which includes a first modulated wavelength of light and a second modulated wavelength of light.

Abstract: Systems and methods are disclosed herein for coherently modulating and demodulating coherent optical signals using 5-bit constellations. The 5-bit constellations have improved suitability for short reach optical communications systems. A first 5-bit constellation can be formed from four rings. The first and fourth rings can form quadrature phase-shift keyed four-symbol sub-constellations, and the second and third rings can form phase-shift keyed twelve symbol constellations. Symbols from the third and fourth sub-constellations are arranged to form a square. A second 5-bit constellation can include an inner 16 symbol sub-constellation and an sixteen symbol outer sub-constellation. Each of the symbols of the inner sub-constellation are equally spaced from its nearest neighboring symbols along both the quadrature and in-phase axes. Each of the symbols in the outer constellation has an equal euclidean-distance with its nearest neighboring symbols in the outer sub-constellation.

Abstract: Optical receivers including at least one local oscillator providing local oscillator light at a local oscillator center frequency offset from a received optical signal by a frequency difference. A combiner for combining the optical signal with the local oscillator light and to output at least one combined optical signal. An opto-electrical converter down-converts the combined optical signal into corresponding RF electrical signal at the frequency of the frequency difference. A filter may be provided to at least substantially remove one of the upper and lower electrical signal sidebands to output one of a VSB and SSB RF signal before rectification. A local oscillator frequency controller may adjustably control the local oscillator frequency to provide the difference frequency that produces a specified group delay in the RF electrical signal that may be specified via optical receiver performance parameters and/or user input and offset using a group delay filter.

Abstract: Techniques that facilitate control of dual phase tuners are provided. In one example, a system includes a first phase tuner and a second phase tuner. The first phase tuner is driven to a first phase bias that is different than a desired phase bias for an interferometer. The second phase tuner is driven to a second phase bias. A combination of the first phase bias and the second phase bias corresponds to the desired phase bias.

Abstract: Embodiments of this disclosure provide a method and apparatus for monitoring a modulation depth of a dither signal and an optical transmitter.

Abstract: An indoor visible light positioning method and system based on a single LED lamp. The system includes an LED communication module and a smartphone module. The LED communication module sends its coordinates and shape data to the smartphone module. The smartphone module includes an inertial measurement unit (IMU) and a camera. The IMU is configured to obtain movement data of a smartphone. The camera is configured to shoot video streams of the LED lamp. Computing processing is performed on center point coordinates of the LED lamp and IMU data in the video streams, and constraints are provided by using a homography matrix of ellipses in the video streams, to obtain accurate location information of the smartphone, and provide location-based services such as navigation and query for a user.

Abstract: A method for compensating the distortions introduced by impairments of MZMz implementing an optical transmitter, according to which the level of total amplitude and phase distortions caused by the optical transmitter is measured and all impairments in the constellation domain are compensated by pre-distorting the input signal to be transmitted by symmetrically adding imbalance to the voltage applied to the MZM arms. The imbalance is determined by introducing a phase rotation in either I or in the Q path of the optical transmitter, which compensates the total amplitude distortion, and also introducing a phase rotation to both I and Q paths of the optical transmitter, which compensate the total phase distortion and the phase shift caused by compensating the amplitude distortion, until reaching a desired operating point, which corresponds to the level of pre-distortion.

Abstract: Techniques and mechanisms for exchanging debug information with a repeater and multiplex logic of a platform. In an embodiment, the multiplex logic can be configured to any of multiple modes including a first mode to exchange debug information between the repeater and debug client logic of the platform. Another of the multiple modes may provide an alternate communication path for exchanging functional data, other than any debug information, between the repeater and a physical layer interface of the platform. In another embodiment, the repeater is compatible with a repeater architecture identified by a universal serial bus standard. The physical layer interface is compatible with an interface specification identified by the same universal bus standard.

Abstract: A signal generation method and an electronic device pertain to the field of communications technologies, and include normalizing an I path of four-level signals and a Q path of four-level signals to obtain a normalized I path of four-level signals and a normalized Q path of four-level signals, mapping the normalized I path of four-level signals and the normalized Q path of four-level signals based on a normalization coefficient to obtain two paths of six-level signals, and driving a dual-drive Mach-Zehnder modulator (DDMZM) based on the six-level signals.

Abstract: Concepts and technologies directed to wireless power transfer network management are disclosed herein. Embodiments of a system can include an optical beamforming transmitter, a processor, and a memory that stores computer-executable instructions that configure a processor to perform operations. The operations can include receiving a power charge message that requests wireless power transfer to charge a battery system of a wirelessly chargeable equipment. The operations can include detecting that the wirelessly chargeable equipment is within a power transfer range of the optical beamforming transmitter. The operations can include determining that the wirelessly chargeable equipment is not stationary. The operations can include tracking movement of the wirelessly chargeable equipment and activating the optical beamforming transmitter that provides wireless power transfer to the wirelessly chargeable equipment while the wirelessly chargeable equipment is within the power transfer range.

Abstract: A method and structure for probabilistic shaping and compensation techniques in coherent optical receivers. According to an example, the present invention provides a method and structure for an implementation of distribution matcher encoders and decoders for probabilistic shaping applications. The techniques involved avoid the traditional implementations based on arithmetic coding, which requires intensive multiplication functions. Furthermore, these probabilistic shaping techniques can be used in combination with LDPC codes through reverse concatenation techniques.

Abstract: An uplink subsystem for use in an illumination system arranged for optical communication as well as the illumination system, the system comprising a downlink subsystem and the uplink subsystem. The uplink subsystem comprises sensors (e.g. infrared sensor) embedded in each luminaire in the group. The uplink subsystem also comprises a demodulator, and a distribution network for supplying the signals sensed to an adaptor to combine instances of the sensed uplink signal in a manner that takes into account a Time Division Medium Access scheme and a demodulator to demodulated the combined signal. The system further comprising a downlink subsystem that in turn comprises a modulator for generating a modulated waveform, and an optical fiber distribution network to distribute the modulated waveform to each luminaire in a group. Each such luminaire generates a drive current for driving a lighting element of that luminaire to emit light.

Abstract: An LED light and communication system is in communication with a broadband over power line communications system. The LED light and communication system includes at least one optical transceiver light fixture. The optical transceiver light fixture includes a plurality of light emitting diodes, at least one photodetector, and a processor. A facility control unit is in communication with the light emitting diode light fixtures and a control server. The facility control unit is constructed and arranged to control the operation of the optical transceiver light fixtures.

Abstract: A waveform matching based optical digital signal receiving device sequentially comprises an optical arbitrary waveform generator unit, an electro-optic modulator unit, an opto-electric converter unit, an electric filter unit, a sampling and judging module, a digital signal processing unit and a bit-timing extracting module. Accordingly, signal matched filtering, sampling and judgment can be effectively carried out in the optical domain, and the influence of noises on signal reception can be eliminated to the maximum extent, thereby achieving accurate detection and reception of signals. Meanwhile, compared with a conventional electric receiving device, the digital signal receiving device provided by the present invention breaks the limitation of “electronic bottleneck,” and greatly improves the bandwidth of signal reception, which allows digital signal reception at a higher speed.

Abstract: Systems and methods are disclosed herein for coherently modulating and demodulating coherent optical signals using 5-bit constellations. The 5-bit constellations have improved suitability for short reach optical communications systems. A first 5-bit constellation can be formed from four rings. The first and fourth rings can form quadrature phase-shift keyed four-symbol sub-constellations, and the second and third rings can form phase-shift keyed twelve symbol constellations. Symbols from the third and fourth sub-constellations are arranged to form a square. A second 5-bit constellation can include an inner 16 symbol sub-constellation and an sixteen symbol outer sub-constellation. Each of the symbols of the inner sub-constellation are equally spaced from its nearest neighboring symbols along both the quadrature and in-phase axes. Each of the symbols in the outer constellation has an equal euclidean-distance with its nearest neighboring symbols in the outer sub-constellation.

Abstract: An embodiment of the inventive concept includes an optical signal generating circuit, a controlling circuit, a waveform shaping circuit, and an output circuit. The optical signal generating circuit generates a first optical signal including pulses. The controlling circuit generates a control signal indicating a first pulse to be attenuated in magnitude among the pulses. The waveform shaping circuit attenuates a magnitude of the first pulse based on the control signal and the first optical signal, and generates a second optical signal including pulses corresponding to the pulses included in the first optical signal and the first pulse having the attenuated magnitude. The output circuit outputs an electric signal of bands corresponding to differences between frequencies of the pulses included in the second optical signal based on the second optical signal. A band corresponding to the first pulse among the bands of the electric signal is adjusted as the magnitude of the first pulse is attenuated.

Abstract: Described herein are optical sensing devices for photonic integrated circuits (PICs). A PIC may comprise a plurality of waveguides formed in a silicon on insulator (SOI) substrate, and a plurality of heterogeneous lasers, each laser formed from a silicon material of the SOI substrate and to emit an output wavelength comprising an infrared wavelength. Each of these lasers may comprise a resonant cavity included in one of the plurality of waveguides, and a gain material comprising a non-silicon material and adiabatically coupled to the respective waveguide. A light directing element may direct outputs of the plurality of heterogeneous lasers from the PIC towards an object, and one or more detectors may detect light from the plurality of heterogeneous lasers reflected from or transmitted through the object.

Abstract: The present application discloses a signal transmitting device based on visible light communication, which includes a first control unit and a visible light emitting unit array, wherein the first control unit is configured to acquire target data and generate a light emission control instruction based on the target data according to a set encoding rule, and the light emission control instruction includes an instruction for controlling the light-dark state of each light emitting unit in the visible light emitting unit array, and the visible light emitting unit array is configured to transmit the target data in form of a visible light signal according to the light emission control instruction. The present application further discloses a signal receiving device based on visible light communication, a visible light communication system and a visible light communication method.

Abstract: Enhancements in optical beam propagation performance can be realized through the utilization of ultra-short pulse laser (USPL) sources for laser transmit platforms, which are can be used throughout the telecommunication network infrastructure fabric. One or more of the described and illustrated features of USPL free space-optical (USPL-FSO) laser communications can be used in improving optical propagation through the atmosphere, for example by mitigating optical attenuation and scintillation effects, thereby enhancing effective system availability as well as link budget considerations, as evidenced through experimental studies and theoretical calculations between USPL and fog related atmospheric events.

Abstract: A photo detector is selectively coupled to a first integrator or a second integrator with switching circuitry when the laser pulses. An integration time of the signal from the photo detector can be substantially greater than an amount of time between successive laser beam pulses in order to provide an accurate measurement of each laser beam pulse of a high repetition rate pulsed laser. The laser may comprise a clock coupled to an optical switch of the laser system, and control circuitry can control switching and coupling of the detector to the first integrator or the second integrator in response to the clock signal. The first integrator and the second integrator can be selectively coupled to an output such that the first integrator or the second integrator is coupled to the output of the energy detection circuitry when the other integrator is coupled to the detector.

Abstract: One example of a system includes an optical modulator, a push-pull driver, and a compensation circuit. The optical modulator has a nonlinear capacitance. The push-pull driver is electrically coupled across the optical modulator. The push-pull driver charges the capacitance in response to a logic ‘1’ of a level-shifted differential signal and discharges the capacitance in response to a logic ‘0’ of the level-shifted differential signal. The compensation circuit increases the speed of the discharge of the capacitance in response to the level-shifted differential signal transitioning from a logic ‘1’ to a logic ‘0’.

Abstract: An apparatus includes an optical data transmitter comprising an optical source of temporally incoherent light, an optical power splitter, an optical mode multiplexer, and a plurality of optical paths. The optical power splitter has an optical input and a plurality of optical outputs. The optical input is connected to receive the temporally incoherent light from the source. The optical mode multiplexer has a plurality of optical inputs and an optical output for connecting to a near end of an all-optical transmission fiber line. Each optical path connects a corresponding one of the optical outputs of the optical power splitter to a corresponding one of the optical inputs of the optical mode multiplexer. One or more of the optical paths of the plurality has or have an optical data modulator. A remaining one of the optical paths of the plurality is configured to transmit reference light from the optical power splitter to optical mode multiplexer.

Abstract: A method and structure for probabilistic shaping and compensation techniques in coherent optical receivers. According to an example, the present invention provides a method and structure for an implementation of distribution matcher encoders and decoders for probabilistic shaping applications. The techniques involved avoid the traditional implementations based on arithmetic coding, which requires intensive multiplication functions. Furthermore, these probabilistic shaping techniques can be used in combination with LDPC codes through reverse concatenation techniques.

Abstract: A method of operating a group of lamps in a multi-lamp luminaire, each lamp being operable to emit respective illumination embedded with a predetermined coded light message, and each comprising a respective local controller; wherein the method comprises: communicating between the local controllers of the lamps within the multi-lamp luminaire in order to coordinate that unsynchronized instances of said coded light message are not transmitted from different ones of the lamps in the multi-lamp luminaire.

Abstract: An optical module includes a semiconductor laser and a linear polarizer that is disposed in an emission direction of the semiconductor laser and that is configured to transmit, of light emitted by the semiconductor laser, only light containing a linearly polarized light component in a specific direction.

Abstract: There is provided a method of transmitting a visible light signal in visible light communication, including binarizing data to be transmitted into a binary bit representation, encoding the data for transmission by modulating one or more of a plurality of light emitting regions between a first state and a second state based on the binary bit representation of the data, and transmitting the visible light signal in the form of light emitted by one or more of the plurality of modulated light emitting regions, the visible light signal being decodable to obtain the data. There is also provided a method of transmitting a visible light signal in visible light communication which includes modulating one or more second sets of light emitting regions within the capture region between a first state and a second state based on the bit representations of one or more previous data for enabling error detection. Corresponding methods of receiving a visible light signal and systems are also provided.

Abstract: An optical transmitter is operative to generate, from a plurality of encoded client bits, a set of symbols exhibiting non-uniform visitation probabilities in at least one dimension, to encode the set of symbols across a plurality of frequency division multiplexing (FDM) subcarriers, and to transmit an optical signal comprising the plurality of FDM subcarriers across which the set of symbols is encoded. An optical receiver is operative to decode a set of symbol estimates from a plurality of FDM subcarriers, the symbol estimates comprising estimates of symbols exhibiting non-uniform visitation probabilities in at least one dimension, and to recover client bits from the set of symbol estimates.

Abstract: A communication network includes a coherent optics transmitter, a coherent optics receiver, an optical transport medium operably coupling the coherent optics transmitter to the coherent optics receiver, and a coherent optics interface. The coherent optics interface includes a lineside interface portion, a clientside interface portion, and a control interface portion.

Abstract: A method for forming a silicon photonics interposer having through-silicon vias (TSVs). The method includes forming vias in a front side of a silicon substrate and defining primary structures for forming optical devices in the front side. Additionally, the method includes bonding a first handle wafer to the front side and thinning down the silicon substrate from the back side and forming bumps at the back side to couple with a conductive material in the vias. Furthermore, the method includes bonding a second handle wafer to the back side and debonding the first handle wafer from the front side to form secondary structures based on the primary structures. Moreover, the method includes forming pads at the front side to couple with the bumps at the back side before completing final structures based on the secondary structures and debonding the second handle wafer from the back side.

Abstract: An optical modulator having a small-sized circuit and a smaller voltage drop in a terminating resistor is provided. The optical modulator includes first and second optical waveguides, a first electrode inputting a first high frequency signal into the first optical waveguide, a second electrode inputting a second high frequency signal having a reverse phase relative to the first high frequency signal into the second optical waveguide, a first terminating resistor connected to the first electrode, a second terminating resistor connected to the second electrode, a connection point connecting the first and second electrodes via the first and second terminating resistors, and a DC voltage supply connected to the connection point. A resistance value of the first terminating resistor is equal to a characteristic impedance of the first electrode. A resistance value of the second terminating resistor is equal to a characteristic impedance of the second electrode.

Abstract: Disclosed are a method and apparatus for demodulating a signal. The method comprises: obtaining a received signal, wherein the received signal comprises a phase noise signal; establishing a likelihood probability ratio integral model on the basis of the received signal and a preset phase noise parameter, wherein the phase noise parameter represents the phase noise signal and is a random variable; performing phase rotation angle extraction and transformation processing and discretization processing on the likelihood probability ratio integral model to obtain a likelihood probability ratio discrete model, wherein the phase rotation angle represents the phase rotation angle obtained on the basis of the phase noise signal; and determining a likelihood probability ratio corresponding to the received signal on the basis of the likelihood probability ratio discrete model to obtain a demodulation result.

Abstract: The present disclosure relates to a method for decoding a combined AM/FM encoded signal, comprising the steps of: combining said encoded optical signal with light from a local oscillator configured with a local oscillator frequency; converting the combined local oscillator and encoded optical signal into one or more electrical signals by means of at least one opto-electrical converter having a predefined frequency bandwidth, thereby providing an amplified and encoded electrical signal having one or more encoded signal current(s), where one type of states have a higher oscillation frequency than other type of states; rectifying the encoded signal current(s), thereby obtaining an encoded power spectrum, wherein said power spectrum has different states, such as “0”-states and “1”-states, with different power levels such that they can be discriminated, said local oscillator frequency is defined by a positive local oscillator frequency-offset from the frequency of one of the states in said encoded optical signal,

Abstract: An optical multiplexer including an optical waveguide block including a plurality of waveguides for adjusting an optical path of the plurality of optical signals. Optical signals generated in light sources having different wavelengths are input to ports of one side that is an input end of the optical waveguide block, propagated through waveguides connected to the ports, and output to ports of another side that is an output end of the optical wavelength block. Intervals between the waveguides decrease in a direction from the input end to the output end. Intervals between the ports of the input end are smaller than intervals between the ports of the output end. The optical waveguide block has a structure in which at least one layer having at least one waveguide is laminated.

Abstract: A transceiver block for multi-user, duplex, wireless access system architecture called Multi Carrier Frequency Modulated Spread Spectrum System (MC FM SS). Here symbols are transmitted at multiple subcarriers where each subcarrier is FM or phase encoded with the data. The data is spread in time/bandwidth using a pseudo-random (PN) sequence. In one realization the transmission is performed with the guard ring carriers and/or pilot subcarriers of an Orthogonal Frequency and Code Division Multiplexing, OFDM, system carried on the main RF carrier. The MC FM SS transmits the data symbol over N subcarriers, with each subcarrier encoded in frequency or phase. In Variable Spreading Factor Orthogonal Frequency and Code Division Multiplexing, VSF OFDM, by DoCoMo Japan with 1024 (which can increase to e.g. 6144) carriers are proposed in Long Term Evolution (LTE) 4G system in the down link direction and 2 carriers MC DS CDMA are used in the uplink direction.

Abstract: A laser including: a gain chip; an external cavity incorporating a Bragg grating; and a baseplate; wherein a first end of the gain chip has a high reflectivity facet forming a first end of the laser cavity; a second end of the gain chip has a low reflectivity facet; and a second part of the external cavity comprises a Bragg grating, supported by the baseplate, the temperature of the baseplate being maintained through a feedback loop; wherein the optical length of the external cavity is at least an order of magnitude greater than the optical length of the gain chip; wherein the Bragg grating is physically long and occupies a majority of the length of the external cavity and is apodized to control the sidemodes of the grating reflection.

Abstract: In a modulation system that modulates and transmits an optical signal over at least one optical fiber in response to an input digital data word of N bits, there is an input enabled for receiving the digital data word; an electrically controllable modulator having one or more waveguide branches, where each branch receives an input of an unmodulated optical signal; and a digital to digital converter enabled for converting the N bits to a digital drive vector corresponding to M drive voltage values, where M>N and N>1. The electrically controllable modulator couples the drive voltage values to the unmodulated optical signal(s). The coupling enables pulse modulation of the unmodulated optical signal(s) thereby generating pulse modulated optical signal(s). The electrically controllable modulator outputs the pulse modulated optical signal(s) to one or more outputs that are enabled for transmitting the pulse modulated optical signal(s) over at least one optical fiber.

Abstract: Remote controllers, positioning systems, and methods configured for the efficient assignment of addresses in a coded lighting positioning system are proposed. Particularly, a proposed remote controller comprises a receiver for receiving coded light from a light source in a coded lighting positioning system, where the coded light comprises an initial light source identifier of the light source. The remote controller also comprises a processing unit for assigning a modified light source identifier to the light source based on the received coded light, and a transmitter for transmitting the modified light source identifier to the light source. The modified light source identifier is a locally unique identifier used to provide positional information.

Abstract: A method and device is provided for reducing optical transmission impairments, particularly nonlinear effects, of at least one link Said method comprising the following steps: extracting a phase information (??) from an optical signal (120) received via that at least one link, determining a nonlinear coefficient (?), associated with the at least one link, based on the phase information (??), applying a control mechanism (202) using the nonlinear coefficient (?). Furthermore, a communication system is suggested comprising said device.

Abstract: An optical time distributor includes: a master clock including: a master comb; a transfer comb; and a free-space optical terminal; and a remote clock in optical communication with the master clock via a free space link and including: a remote comb that produces: a remote clock coherent optical pulse train output; a remote coherent optical pulse train; a free-space optical terminal in optical communication: with the remote comb; and with the free-space optical terminal of the master clock via the free space link, and that: receives the remote coherent optical pulse train from the remote comb; receives the master optical signal from the free-space optical terminal of the master clock; produces the remote optical signal in response to receipt of the remote coherent optical pulse train; and communicates the remote optical signal to the free-space optical terminal of the master clock.

Abstract: A dummy-light generating device includes a continuous wave (CW) light source that outputs CW light, a modulated-light generating unit that generates, using the CW light, first intensity-modulated light subjected to intensity modulation and second intensity-modulated light delayed by a half time of a modulation cycle of the first intensity-modulated light with respect to the first intensity-modulated light and having a polarization state e different from a polarization state e of the first intensity-modulated light, and a polarization combiner that performs polarization combination of the first intensity-modulated light and second intensity-modulated light and outputs light after the polarization combination as dummy light.