Abstract: A laser system includes a first laser cavity to output a laser light along a first path, a first mirror to receive the laser light from the first laser cavity, and redirect the laser light along a second path that is different than the first path, a second mirror to receive the laser light from the first mirror, and redirect the laser light along a third path that is different than the first path and the second path, a beam splitter located at a first position on the third path, a beam combiner located at a second position on the third path; and a coupling lens assembly, the coupling lens assembly including a lens located at a third position on the third path, wherein the coupling lens assembly moves the lens in x-, y-, and x-directions.

Abstract: The present invention relates to a remote tomography system. A filament system generates at least one plurality of plasma filaments. An electromagnetic radiation (EMR) system directs EMR towards the at least one plurality of plasma filaments such that the EMR reflects off of the at least one plurality of plasma filaments towards at least one target region. The EMR system is configured to receive EMR reflected from the at least one plurality of plasma filaments such that EMR reflecting from the at least one target region can be directed towards the EMR system.

Abstract: Provided are a data modulation method and apparatus, a device, and a storage medium. The data modulation method includes that: a modulation manner is configured, where a constellation point modulation symbol of the modulation manner is formed by combining a first group of constellation point modulation symbols and a second group of constellation point modulation symbols; and data is modulated by using the modulation manner, where the data includes a first data block and a second data block, the first data block is modulated by the first group of constellation point modulation symbols, and the second data block is modulated by the second group of constellation point modulation symbols.

Abstract: Systems and methods are disclosed for two-dimensional optical transmission, including systems and methods for modulating and detecting two-dimensional short-reach optical communications. Two-dimensional optical transmissions may be generated by mapping a first data set to a first dimension of an optical signal and mapping a second data set to a second dimension of an optical signal. The encoded data for the first data set may be combined with the encoded data for the second data set so as to produce drive signals for a dual-drive modulator using a combination of both a common-mode and differential signal. The disclosed systems and methods also include dual-mode optical receivers that are configured to operate in either a one-dimensional or two-dimensional mode.

Abstract: A system and related method for multiple-sensitivity optical phase modulation splits an optical carrier generated by a photonic source into at least two copies and directs the copies (e.g., via optical circulators or polarization rotators) to an electro-optical (EO) phase modulator such that the phase modulator phase-modulates each optical copy according to a received radio frequency (RF) signal of interest based on characteristics distinct to each optical copy (e.g., optical path direction, signal polarization) that provide for phase modulation of each optical copy at a different sensitivity voltage. The variably modified optical copies are directed to a photonic processor for further signal processing in the optical domain.

Abstract: An optical transmitter device (14) includes a digital signal processor ‘DSP’ (20) having digital hardware (30). The DSP is operative to generate (102,202,302) shaped bits from a first set of information bits, and to apply (104,204,304) a systematic forward error correction ‘FEC’ scheme to encode the shaped bits and a second set of information bits, where the first set of information bits and the second set of information bits are disjoint sets. Unshaped bits and the shaped bits are mapped to selected symbols or are used to select symbols from one or more constellations. The selected symbols are mapped to physical dimensions. Each unshaped bit is either one of the second set of information bits or one of multiple parity bits resulting from the FEC encoding. In this manner, a target spectral efficiency is achieved.

Abstract: In an aspect, a pressure sensor for determining pressure in an environment comprises: a source for emitting a coherent reference light characterized by a reference light frequency; a first lock-in mechanism configured to send an electrical signal to the source based on a reference resonance frequency; a reference cavity; wherein the reference cavity is characterized by the reference resonance frequency; a modulator configured a reference light to generate at least a first sideband frequency such that an output of said modulator is a measurement light characterized by at least the first sideband frequency; a frequency synthesizer configured to drive the modulator; a second lock-in mechanism configured to send an electrical signal to the frequency synthesizer based on a measurement resonance frequency; and a measurement cavity configured to receive at least a portion of the measurement light; wherein the measurement cavity is characterized by the measurement resonance frequency; and wherein the pressure of the

Abstract: A polarization multiplex optical transmitter circuit can provide compensation for the transmission PDL while reducing decrease in transmission power. The polarization multiplex optical transmitter circuit includes a beam divider circuit configured to divide light outputted from a light source, optical phase shifters provided in at least one of two waveguides connected to output terminals of the beam divider circuit, a light wave synthesizer circuit connected to the two waveguides, first and second optical transmitters coupled to two output terminals of the light wave synthesizer circuit, a polarization multiplexer configured to synthesize two output polarized waves from the first and second optical transmitters, and a polarization rotator provided between the first and second optical transmitters and the polarization multiplexer and coupled to at least one of the first and second optical transmitters.

Abstract: There is described an optical phase modulator generally having a substrate; a waveguide mounted to the substrate and extending along a path of the substrate, the waveguide having a first series of phase shift units distributed along the waveguide, each phase shift unit having two Bragg gratings being spaced apart from one another along the path and a cavity between the two spaced-apart Bragg gratings; and a modulation circuit configured for driving a length of the series of phase shift units of the waveguide in accordance with a modulation signal thereby modulating a refractive index of the waveguide to induce a phase shift to an optical signal propagating along the waveguide.

Abstract: In a streaming application environment coupled to a remote device over a packet-switching network, correction events may be synthesized from input events received from the remote device and injected into a virtual streaming application to account for lost or delayed input events. In addition, trailing events may be reissued by a remote device in frames during which no new input events are generated.

Abstract: Systems and methods for generating indistinguishable Glauber-state and decoy-state optical signals. In one implementation, the system includes a direct current (“DC”) current source, a configurable pulse generator, an electronic controller, and a laser diode. The electronic controller is configured to control the DC current source to apply a bias signal to a node. The electronic controller is further configured to control the configurable pulse generator to apply Glauber-state excitation current pulses to the node to generate Glauber-state current injection pulses. The electronic controller is also configured to control the configurable pulse generator to apply decoy-state excitation current pulses to the node to generate decoy-state current injection pulses. An amplitude of the decoy-state current injection pulses is less than an amplitude of the Glauber-state current injection pulses.

Abstract: An optically biased photonic link receives a radio frequency (RF) signal and includes a signal laser joined to an optical intensity modulator. A low noise amplifier receives the RF signal and provides an amplified signal to the modulator. The modulator converts the signal into an optical signal. The amplifier and modulator are powered by a photovoltaic array. The array receives power from a remotely located power laser. The optical signal is received by a link receiver which provides an analysis signal and an output signal. A bias logic circuit uses the analysis signal to provide an optical bias signal to an optical detector joined to modulator. The optical detector provides a responsive bias voltage to the modulator.

Abstract: A system and method for metrology and profilometry using a light field generator are disclosed. For this purpose, a system such as an optical analysis system scans a sample using light, and detects light reflected off a sample in various ways. The system operates different operational modes including a backscatter intensity, a triangulation, and an interferometric mode. For this purpose, the optical analysis system includes one or more optical angle modulation systems, such as surface acoustic wave (SAW) modulators, that emit light, a sample holder, and a scanning system that scans the one or more SAW modulators relative to the sample holder. The system performs tomographic reconstructions of information generated by the scans to create 3D maps/volume datasets of the sample.

Abstract: An optical transmitter includes a bias supplying unit configured to supply a first bias voltage, a second bias voltage and a third bias voltage to an optical modulator. The bias supplying unit acquires a first voltage value at which an average value of an optical output signal becomes maximum by sweeping the first bias voltage, acquires a second voltage value at which an average value of the optical output signal becomes maximum by sweeping the second bias voltage, and acquires a third voltage value at which an average value of the optical output signal becomes maximum by sweeping the third bias voltage. The bias supplying unit determines a value of the first bias voltage based on the first voltage value, determines a value of the second bias voltage based on the second voltage value, and determines a value of the third bias voltage based on the third voltage value.

Abstract: A first optical splitter splits a light source to obtain a first optical signal, a second optical signal, and a third optical signal. A first MZ modulator modulates the first optical signal to output a fourth optical signal. A second MZ modulator modulates the second optical signal to output a fifth optical signal. A first optical coupler couples the fourth optical signal and the fifth optical signal to output a sixth optical signal and a seventh optical signal. A power regulator and a phase shifter respectively perform power adjustment and phase shifting on the third optical signal to output an eighth optical signal. A second optical splitter splits the eighth optical signal into a ninth optical signal and a tenth optical signal. A second optical coupler combines the sixth optical signal and the ninth optical signal. A third optical coupler combines the seventh optical signal and the tenth optical signal.

Abstract: An optical receiver includes: a first combiner configured to output first combined light by combining local light of first polarization and signal light of second polarization; a converter configured to convert the first combined light to a first electric signal; a converter configured to covert a component of the first combined light that has passed through a first polarizer to a second electric signal; a converter configured to convert a component of the first combined light that has passed through a wave plate and a polarizer to a third electric signal; a divider configured to output a fourth electric signal and a fifth electric signal by branching the first electric signal; subtractors configured to subtract the fourth electric signal from the second electric signal and the fifth electric signal from the third electric signal.

Abstract: A method for configuring hardware-configured optical links includes generating a first optical signal comprising a slow scan of wavelength channels where the slow scan has a dwell time on a particular wavelength channel. A second optical signal is generated comprising a fast scan of wavelength channels, where the fast scan has a dwell time on a particular wavelength channel and a complete channel scan time where the slow scan dwell time is greater than or equal to complete channel scan time. The first optical signal is transmitted over a link and a portion is then detected. A pulse of light having a duration that is less than the dwell time on the particular wavelength channel of the fast scan is then detected. Client data traffic is then sent over the link in response to the detected pulse of light and the detected portion of the first optical signal.

Abstract: In some embodiments, an apparatus includes a quadrature amplitude modulation (QAM) optical modulator which includes a first phase modulator (PM), a second PM, a tunable optical coupler (TOC), and an optical combiner (OC). The TOC is configured to split a light wave at an adjustable power splitting ratio to produce a first split light wave and a second split light wave. The first PM is configured to modulate the first split light wave in response to a first multi-level electrical signal to produce a first modulated light wave. The second PM is configured to modulate the second split light wave in response to a second multi-level electrical signal to produce a second modulated light wave. The OC is then configured to combine the first modulated light wave and the second modulated light wave to generate a QAM optical signal.

Abstract: An optical interference modulator comprises a main input, a main output, an optical splitter connected to the main input, first and second MMI couplers, each with a first primary-end access port connected to the splitter; a second primary-end access port connected to the main output; a first secondary-end access port connected to a respective primary waveguide; and a second secondary-end access port connected to a respective secondary waveguide. A light reflector is arranged to reflect light incident from said primary and secondary waveguides back into the same respective waveguide such that light travelling through the respective waveguide from the respective secondary-end access port, after reflection, travels back to the same secondary-end access port. For the MMI couplers, at least one of the respective primary and secondary waveguides comprises a respective light phase modulating device arranged to modulate the phase of light travelling along the corresponding waveguide in either direction.

Abstract: There is provided an optical transmitter including a modulator, a signal generator configured to generate in-phase or anti-phase skew adjustment signals that are identical in amplitude and frequency as signals to be input into an I axis and a Q axis of the modulator, a skew adjuster configured to perform skew adjustment upon the skew adjustment signals, a light source configured to enter light into the modulator, a monitor configured to monitor light that has been modulated using the skew adjustment signals and output from the modulator, a power detector configured to detect power of monitor light, and a controller configured to determine a skew adjustment amount with which average power of the monitor light is at a maximum or minimum value as an optimum skew adjustment value while changing a skew adjustment amount of the skew adjuster.

Abstract: Apparatus for controlling a plurality of active illumination cameras to operate in a frequency division multiplexed operating mode to acquire images of scenes that the cameras image.

Abstract: Apparatus for controlling a plurality of active illumination range cameras to operate in a time division multiplexed operating mode to acquire range images of scenes that the cameras image.

Abstract: An optical transceiver includes an optical transmitter configured with data pre-coding to support integrating and resetting functions in a corresponding self-resetting integrating optical receiver; and a self-resetting integrating optical receiver comprising dual photodetectors connected to a capacitor, wherein the dual photodetectors and the capacitor are configured to perform the integrating and resetting functions based on a pre-coded optical input from a corresponding optical transmitter. The data pre-coding can include a 0 differential phase indicative of a 1 bit to set a charge on the capacitor for setting function, +/??/2 differential phase indicative of a hold so that the charge on the capacitor is held at a previous value by delivering equal intensity to the dual photodetectors for a holding function, and a ? differential phase indicative of a 0 bit to reset the charge on the capacitor to zero for resetting function.

Abstract: Embodiments of the present disclosure are directed toward techniques and configurations for an apparatus comprising an electro-optical modulation device with a bias control and adjustment. In some embodiments, the apparatus may comprise an electro-optical modulator having first and second arms, to modulate light passing through the first and second arms in response to an input data signal, and output a corresponding optical data signal. The apparatus may further comprise a control module coupled with the electro-optical modulator, to differentially adjust respective phases of first or second light portions passing through the first and second arms, to achieve a bias point for the optical data signal. The bias point may define a desired power output of the apparatus that corresponds to the optical data signal. Other embodiments may be described and/or claimed.

Abstract: Disclosed herein is a dual parallel Mach-Zehnder-modulator (DPMZM) device comprising a DPMZM 10 having first and second inner MZMs arranged parallel to each other. The first inner MZM generates an in-phase component EI of an optical signal in response to a first driving voltage VI, and the second inner MZM generates a quadrature component EQ of said optical signal in response to a second driving voltage VQ. Further disclosed is a calculation unit 52 configured for receiving an in-phase component yI and a quadrature component yQ_ of a desired base-band signal, and for calculating pre-distorted first and second driving voltages VI, VQ. The calculation of the pre-distorted first and second driving voltages VI, VQ is based on a model of said DPMZM 10 accounting for I-Q cross-talk, and using an algorithm that determines said first and second driving voltages VI, VQ each as a function of both of said in-phase and quadrature components yI, yQ of said base-band signal.

Abstract: Constant modulus multi-dimensional modulation system and methods are disclosed herein, employing multi-intensity quadrature amplitude modulation (QAM) to generate a dual-polarization symbol. j bits may be mapped to one of a plurality of dual-polarization symbols having a same constant power modulus on a two-level constellation including first and second intensity rings in a four-dimensional (4D) space including in-phase (I), quadrature (Q), X polarization (Xpol) and Y polarization (Ypol). A first bit of the j bits may indicate that the symbol is on the first intensity ring for the Xpol and the second intensity ring for the Ypol, a next k bits may indicate a location of the symbol on the first intensity ring in the Xpol, and a remaining j?k?1 bits may indicate a location of the symbol on the second intensity ring in the Ypol. Maximum correlation decoding may be used to decode the first symbol at the receiver.

Abstract: Embodiments of the present invention pertain to optical wireless architecture. More particularly, certain embodiments of the invention pertain to a novel method and apparatus to generate millimeter-wave signals with simple and/or low cost architecture. Simple millimeter-wave generation and dispersion-tolerant transmission is based on photonic mixing of two free-running lightwaves and self-mixing down-conversion. More particularly, heterodyne mixing of two free run lightwaves is achieved, wherein one lightwave is modulated by an external modulator driven by electrical data as one of the side-bands of a millimeter-wave signal. Optical to electrical conversion is performed and the millimeter-wave signal is broadcasted by a high-frequency antenna to a receiving side having a local oscillator with self-mixing architecture to down-convert the radio frequency to its baseband form.

Abstract: An electro-optical modulator includes a substrate comprising a first Mach-Zehnder modulator comprising a first waveguide and a second waveguide and a second Mach-Zehnder modulator comprising a first waveguide and a second waveguide. A first positive signal electrode is positioned on the substrate over the first waveguide of the first Mach-Zehnder modulator and a first negative signal electrode is positioned on the substrate over the second waveguide of the first Mach-Zehnder modulator. The first positive signal electrode and the first negative signal electrode are connected to a first differential signal input. A second positive signal electrode is positioned on the substrate over the first waveguide of the second Mach-Zehnder modulator and a second negative signal electrode positioned on the substrate over the second waveguide of the second Mach-Zehnder modulator. The second positive signal electrode and the second negative signal electrode are connected to a second differential signal input.

Abstract: A satellite communication system may include a communication satellite orbiting Earth, a user terminal in radio communication with the communication satellite through a user link, a communication relay apparatus operating at an altitude of approximately 65,000 feet and in optical communication with the communication satellite through a feeder link, and a gateway station in radio communication with the communication relay apparatus through a gateway link.

Abstract: A distributed traveling-wave Mach-Zehnder modulator driver having a plurality of modulation stages that operate cooperatively (in-phase) to provide a signal suitable for use in a 100 Gb/s optical fiber transmitter at power levels that are compatible with conventional semiconductor devices and conventional semiconductor processing is described.

Abstract: A touch sensor includes a touch panel including driving lines and sensing lines and having node capacitors between neighboring or overlapping driving lines and sensing lines, a driving unit configured to modulate driving signals using a direct sequence spread spectrum technique or scheme and simultaneously drive two or more of the driving lines using the modulated driving signals, and a sensing unit configured to demodulate the signals from the sensing lines using the direct sequence spread spectrum method and generate demodulated signals.

Abstract: Systems and methods of performing logical operations with photonic quantum logic gates. The logic gates utilize photon states, usually orthogonal linearly polarized states, to selectively enact self-interference operations whose outputs can be altered by inducing phase shifts in one or more portions of the section of the logic gate where the photon states undergo self-interference. The polarization direction switchings are differentially enacted and/or not enacted, in groupings of switches, to perform various logic operations. Additionally, networked logic gates with interrelated self-interference section phase shifts and output states are described that provide additional capabilities.

Abstract: An apparatus comprising a digital signal processor (DSP) unit configured to perform fiber dispersion pre-compensation on a digital signal sequence based on a dispersion value to produce a pre-compensated signal, wherein the dispersion value is associated with a remote optical receiver, a plurality of digital-to-analog converters (DACs) coupled to the DSP unit and configured to convert the pre-compensated signal into analog electrical signals, and a frontend coupled to the DACs and configured to convert the analog electrical signals into a first optical signal, adding a constant optical electric (E)-field to the first optical signal to produce a second optical signal, and transmit the second optical signal to the remote optical receiver.

Abstract: An optical transmitter includes: optical modulation means; bias voltage output means for supplying the optical modulation means with a bias voltage on which a pilot signal is superimposed; pilot signal receiving means; and bias voltage control means. The bias voltage control means includes: training means for determining a control start voltage and a control direction of the bias voltage based on a pilot signal component at first and second bias voltage values; and feedback means for determining an appropriate bias voltage to compensate for a deviation of an operating point of the optical modulation means by analyzing the pilot signal component while adjusting the bias voltage in a stepwise fashion along the control direction from the control start voltage after the control start voltage and the control direction are determined.

Abstract: A transmitter with at least one optical modulator adapted to modulate the optical signal output by a laser source to generate a modulated optical signal, wherein the optical signal output by the laser source is tapped and supplied to a monitoring circuit comprising an optical front end configured to select signal components of the tapped modulated optical signal and to convert the selected signal components of the tapped modulated optical signal into analog signals, and comprising at least one analog-to-digital converter, ADC, adapted to perform equivalent-time sampling of the analog signals to provide digital signals processed by a processing unit to monitor signal quality of the modulated optical signal.

Abstract: An optical transmitter for modulating light from a light source to generate an optical transmission signal with use of a data sequence as an electric signal, the optical transmitter including: a mapping section for mapping the data sequence to be converted into multi-level data based on modulation multi-level degree information indicating multi-level degree of the modulation; a D/A converter for converting the multi-level data output from the mapping section into an analog signal; an optical modulator to be driven based on the analog signal output from the D/A converter, for modulating the light from the light source; and a bias control section for setting control polarity of DC bias control of the optical modulator based on the modulation multi-level degree information.

Abstract: Since it is difficult to control correctly and optimally the DC biases of an IQ modulator driven with pre-equalized data, a method for controlling an optical transmitter according to an exemplary aspect of the invention includes the steps of (a) making direct current biases for driving children Mach-Zehnder modulators of an IQ modulator in the optical transmitter converge to values close to null driving points of the children Mach-Zehnder modulators, (b) driving the children Mach-Zehnder modulators with special driving data including a pair of training patterns between which there is a significant correlation, (c) scanning direct current biases for setting quadrature angle of the IQ modulator, (d) monitoring output of the IQ modulator during step (c), and (e) setting the direct current bias for setting quadrature angle on the basis of the driving data and monitored results in step (d).

Abstract: The present invention discloses a QPSK signal conjugate relationship identification method and apparatus. The method includes: receiving a first binary sequence signal, using the first binary sequence signal to modulate an optical signal, and determining, within a first predetermined range, a first bias voltage in a QPSK modulator; receiving a second binary sequence signal, using the second binary sequence signal to modulate the optical signal, determining a second range within the first predetermined range according to the first bias voltage, and determining, within the second range, a second bias voltage in the QPSK modulator; and determining a conjugate relationship of the QPSK signal according to a value relationship between the first bias voltage and the second bias voltage. The present invention features low costs and a small component size.

Abstract: Disclosed are structures and methods for generating a Nyquist superchannel.

Abstract: Embodiments of the present disclosure relate to a signal transmission method The signal receiving method includes: receiving a first transmit signal, where the first transmit signal includes a first polarized optical signal and a second polarized optical signal that are perpendicular to each other, where the first polarized optical signal is loaded with first data, the first transmit signal is an uplink signal, and the first data is uplink data, or, the first transmit signal is a downlink signal, and the first data is downlink data; splitting the first transmit signal into a first signal and a second signal according to power; separately rotating a first polarized optical signal and a second polarized optical signal of the second signal by 90 degrees; and performing coherent mixing on the rotated second signal and the first signal to obtain the first data.

Abstract: There is described an optical modulation system for transmitting modulated optical light. The system comprises an electro-optic modulator having at least two arms through which light is transmitted and an imbalance electrode located on at least one arm. A current source is configured to inject current into the imbalance electrode for modifying the phase of light passing through the arm. A dither generator is configured to modulate the injected current, or bias voltage applied to at least one of the arms, with a dither signal. A phase sensitive detector is configured to detect an error in the phase of light emitted by the modulator. An operating point controller is configured to monitor the detected phase error and adjust the current injected into the imbalance arm so as to compensate for the detected error and thereby control an operating point of the modulator.

Abstract: A transmitter module includes a processor configured to receive input data, and determine input values corresponding to the input data; a digital-to-analog converter configured to receive the input values from the processor, and generate first and second voltage signals based on the input values; a laser configured to output light; a Mach-Zehnder modulator configured to receive the light from the laser and the first and second voltage signals from the digital-to-analog converter, and modulate the light based on the first and second voltage signals to generate a modulated optical signal that includes distortion; and a filter configured to receive the modulated optical signal from the modulator, process the modulated optical signal to reduce or eliminate the distortion and produce an output optical signal, and output the output optical signal.

Abstract: This invention concerns real-time multi-impairment signal performance monitoring. In particular it concerns an optical device, for instance a monolithic integrated photonics chip, comprising a waveguide having an input region to receive a signal for characterization, and a narrow band CW laser signal. A non-linear waveguide region to mix the two received signals. More than one output region, each equipped with bandpass filters that extract respective discrete frequency bands of the RF spectrum of the mixed signals. And, also comprising (slow) power detectors to output the extracted discrete frequency banded signals.

Abstract: The present invention discloses a QPSK signal conjugate relationship identification method and apparatus. The method includes: receiving a first binary sequence signal, using the first binary sequence signal to modulate an optical signal, and determining, within a first predetermined range, a first bias voltage in a QPSK modulator; receiving a second binary sequence signal, using the second binary sequence signal to modulate the optical signal, determining a second range within the first predetermined range according to the first bias voltage, and determining, within the second range, a second bias voltage in the QPSK modulator; and determining a conjugate relationship of the QPSK signal according to a value relationship between the first bias voltage and the second bias voltage. The present invention features low costs and a small component size.

Abstract: After a startup of an optical transmitter, a control is started in such a way that a modulation amplitude of a driving signal of a phase modulator is set as 0, and that an operational point of a bias voltage is set as the lowest point of light transmission characteristics of the phase modulator. When the operational point of the bias voltage reaches the lowest point, the modulation amplitude of the driving signal is gradually increased from 0 to 2V?.

Abstract: An optical signal transmitter of the present invention includes: two phase modulating portions; a phase shifter which displaces carrier phases of two output lights from the phase modulating portions by ?/2; a multiplexing portion which multiplexes two signal lights, carrier phases of the two signal lights being made orthogonal to each other by the phase shifter; a drive signal electrode portion which supplies a differential data signal to each of four paths of interference optical waveguides, each of the two phase modulating portions having the interference optical waveguides, the differential data signal having an amplitude which is equal to a half-wave voltage V? of the two phase modulating portions; a drive amplifier which amplifies the differential data signal to be supplied to each of the four paths of the interference optical waveguides; a data bias electrode portion which supplies a total of four data bias voltages to two arms, each of the two phase modulating portions having the two arms; an orthogona

Abstract: Phase shift keying optical modulation apparatus comprising optical phase shifting apparatus and an optical modulator. The optical phase shifting apparatus is arranged to receive an optical carrier signal and is arranged to selectively apply a preselected optical phase shift to the optical carrier signal in dependence on a symbol of a 2N-level phase shift keying modulation format to be encoded onto the optical signal. The optical modulator is arranged to receive the optical carrier signal from the optical phase shifting apparatus and is arranged to apply a phase modulation to the optical carrier signal in dependence on the symbol, to thereby encode the symbol onto the optical carrier signal. The phase modulation is a phase-modulation of an N-level phase shift keying modulation format.

Abstract: Provided is a working point controlling device and method for applying MZ modulator, which includes: a light modulator; a transimpedance amplifier, transmits current outputted by PD of the modulator into voltage signal; a low-noise amplifier, detects low-frequency signal and amplifies the signal, in order to improve the signal/noise ratio; a high Q band-pass filter, detects error signal and amplifies the signal, in order to improve the signal/noise ratio; a first power level conditioning, performs power level condition on error signal of phase, in order that signal output meets A/D input rang; a micro processor, generates low-frequency signal and finishes software synchronization detection wave and ratio integration PI adjusting algorithm; a second power level conditioning, finishes D/A output voltage condition, in order that D/A output is able to meet direct current offset whole controlling range power voltage range of the light modulator.

Abstract: The optical frequency comb generating device having two optical modulation parts 41 and 42 independently modulating optical waves propagating in two branch waveguides and a phase regulator 43 controlling a phase difference between the optical waves includes amplitude adjusting means 22 for adjusting a voltage amplitude of the RF signal supplied to at least one of the optical modulation parts, monitoring means 21 for monitoring the intensity Pout of the output light beam, and a bias control circuit 20 that controls the amplitude adjusting means to change a difference in voltage amplitude between the RF signals supplied to each optical modulation part, that detects a variation of the output light beam corresponding to the variation of the difference in voltage amplitude from the output signal of the monitoring means, and that controls the phase regulator on the basis of the detection result to adjust the phase difference.

Abstract: An optical semiconductor device includes: an active region which includes an active layer which produces light when current is injected therein, a first diffraction grating layer having a first diffraction grating with a prescribed grating period, and a phase shift portion formed within the first diffraction grating layer, wherein the phase shift portion provides a phase shift not smaller than 1.5? but not larger than 1.83?; and a distributed reflection mirror region which is optically coupled to a first end of the active region as viewed along a direction of an optical axis, and which includes a second diffraction grating which reflects the light produced by the active region back into the active region.