Abstract: A display device includes an organic EL element layer, a liquid crystal element layer disposed on top of the organic EL element layer, and a polarizing plate disposed at a side of the liquid crystal element layer that faces an observer. The liquid crystal element layer includes two transparent substrates and a liquid crystal layer disposed between the two transparent substrates. The liquid crystal element layer is configured to be able to, by applying a voltage to the liquid crystal layer, cause a substantially quarter-wavelength retardation in light passing through the liquid crystal layer.

Abstract: The application discloses a polarization independent DQPSK demodulation integrated optical chip, which comprises a first beam splitter, a first polarization beam splitter rotator, a second beam splitter, a third beam splitter, a first quarter-wave plate, a first delayed optical waveguide, and a second polarization beam splitter rotator that are integrated on a same substrate.

Abstract: A display device including a meta surface is provided. The display device includes an image provider comprising a spatial light modulator configured to modulate light according to image information, wherein the image provider is configured to provide the light comprising the image information; an optical element configured to focus the light from the image provider; and a meta surface deflector positioned between the image provider and the optical element to deflect the light, and change a deflection direction of the light according to a polarization of the light so that a first position of the light of a first polarization focused by the optical element is different than a second position of the light of a second polarization orthogonal to the first polarization focused by the optical element.

Abstract: A system for creating an adjustable delay in an optical signal. The system has an input interface for receiving an optical input signal. The system has a first optical modulator configured to shift the frequency of the optical input signal depending on a setting of the first optical modulator, thereby generating a modulated optical signal. The system includes at least two frequency selective reflectors configured to reflect the modulated optical signal, thereby providing a reflected signal. The system has a control circuit that adapts the setting of the first optical modulator such that a frequency shift of the optical input signal introduced by the first optical modulator is set by the control circuit. The frequency shift introduced by the first optical modulator corresponds to an operational frequency of one of the at least two frequency selective reflectors associated with the setting of the first optical modulator.

Abstract: Communicating polarization-dependent information over a free space channel may include separating a data signal carrying data into a first signal and a second signal each carrying a portion of the data of the data signal, modulating a first carrier signal with the first signal and a second carrier signal with the second signal, radiating the modulated first signal with a first polarization as a polarized first signal over a free space channel, radiating the modulated second signal with a second polarization as a polarized second signal over the free space channel, demodulating the polarized first signal and the polarized second signal, and combining the demodulated first signal with the demodulated second signal to provide an output signal carrying the data of the data signal.

Abstract: A range finding apparatus (2000) generates a plurality of range finding signals. The range finding apparatus (2000) generates transmission light acquired by performing at least one of quadrature modulation and polarization modulation on an optical carrier wave by using each of the generated range finding signals. The range finding apparatus (2000) transmits the generated transmission light. The range finding apparatus (2000) receives reflection light which is the transmission light reflected by an object to be measured. The range finding apparatus (2000) extracts a reception signal corresponding to each of the range finding signals by demodulating the reflection light. The range finding apparatus (2000) computes a distance to the object to be measured by using any one or more of the extracted reception signals.

Abstract: An optical transmission system includes: a transmission unit configured to co-propagate a signal light in which data is modulated and an idler light having complex amplitude that is phase conjugate with the signal light via an optical transmission medium; at least one optical amplifier configured to perform a phase sensitive amplification operation through an action among the signal light, the idler light, and an excitation light in a nonlinear medium; and a reception unit configured to receive the signal light that has been amplified by the optical amplifier, coherently detect the signal light and the idler light individually, and conduct a diversity synthesis to demodulate the data.

Abstract: Provided are a light detection element, a receiving device, and a light sensor device. The light detection element includes a magnetic element that includes a first ferromagnetic layer, a second ferromagnetic layer, and a spacer layer interposed between the first ferromagnetic layer and the second ferromagnetic layer, wherein the first ferromagnetic layer is irradiated with light in a direction intersecting a stacking direction of the magnetic element.

Abstract: A receiving device includes a magnetic element having a first ferromagnetic layer, a second ferromagnetic layer, and a spacer layer sandwiched between the first ferromagnetic layer and the second ferromagnetic layer, wherein the first ferromagnetic layer is configured to be irradiated with light containing an optical signal with a change of intensity of the light, and wherein the receiving device is configured to receive the optical signal on a basis of an output voltage from the magnetic element.

Abstract: An optical transmission device includes a first wavelength multiplexer, a second wavelength multiplexer, a wavelength converter and a third wavelength multiplexer. The first wavelength multiplexer multiplexes optical signals in a first wavelength band to generate first wavelength multiplexed light. The second wavelength multiplexer multiplexes optical signals in the first wavelength band to generate second wavelength multiplexed light in a first polarization. The wavelength converter converts a wavelength of the second wavelength multiplexed light from the first wavelength band into a second wavelength band by a cross phase modulation among the second wavelength multiplexed light, first pump light in a second polarization and second pump light in the second polarization. The second polarization is orthogonal to the first polarization.

Abstract: An example system includes a first network device having first circuitry. The first network device is configured to perform operations including receiving data to be transmitted to a second network device over an optical communications network, and transmitting first information and second information to the second device. The first information is indicative of the data, and is transmitted using a first communications link of the optical communications network and using a first subset of optical subcarriers. The second information is indicative of the data, and is transmitted using a second communications link of the optical communications network and using a second subset of optical subcarriers. The first subset of optical subcarriers is different from the second subset of optical subcarriers.

Abstract: An EHz ultrafast modulated pulse scanning laser and a distributed fiber sensing system. A plurality of phase-shift gratings are engraved on a doped fiber, the phase-shift gratings having different central window wavelengths and a wavelength interval between the adjacent central window wavelengths being a preset fixed value. When a pump light emitted by a pump laser source is coupled by a wavelength division multiplexer and enters the doped fiber, a single-mode narrow-linewidth laser light having multiple wavelengths with a wavelength interval being a preset fixed value can be generated, by using the phase-shift gratings graved on the doped fiber. The ultrafast modulation is completed by using a time-domain control method based on an EOM. An internally frequency converted pulse light formed by splicing pulse lights whose frequencies linearly increase is obtained, thus forming the EHz ultrafast modulation of a distributed feedback fiber laser.

Abstract: An example system includes a first network device having first circuitry. The first network device is configured to perform operations including receiving data to be transmitted to a second network device over an optical communications network, and transmitting first information and second information to the second device. The first information is indicative of the data, and is transmitted using a first communications link of the optical communications network and using a first subset of optical subcarriers. The second information is indicative of the data, and is transmitted using a second communications link of the optical communications network and using a second subset of optical subcarriers. The first subset of optical subcarriers is different from the second subset of optical subcarriers.

Abstract: The present invention provides a configuration of a novel optical transmitter which outputs stable PDM signals. The novel optical transmitter generates phase conjugate light using a single second-order non-linear optical element included in a phase conjugate light generator with a looped configuration. A relative phase of main signal light with respect to excitation light and phase conjugate light of the main signal light stabilizes between two polarized components, and a PDM signal including a pair of a polarization-multiplexed signal and phase conjugate light in a stable phase state can be generated and transmitted. The present invention can provide an optical transmitter that generates a PDM signal in which a variation in a phase between quadrature polarized waves is suppressed. By stabilizing quality of a PDM transmission signal on a side of the optical transmitter, a phase sensitive amplifier in a polarization diversity configuration can be operated in a stable manner.

Abstract: According to one embodiment, a transmitting device for a quantum key distribution system includes a light source, a beam splitter, an encoder, and a beam combiner. The light source is configured to generate an optical pulse. The beam splitter is configured to split the optical pulse into a signal pulse that travels through a first path and a polarization control pulse that travels through a second path, the second path being different in an optical path length from the first path. The encoder is provided at the first path and is configured to encode information with respect to the signal pulse. The beam combiner is configured to combine the signal pulse passing through the encoder and the polarization control pulse.

Abstract: A polarization dependent loss (PDL) compensation device for an optical system can be configured to output a compensating PDL to at least partially cancel a PDL of the optical system. In certain embodiments, the device can include a first polarization controller configured to modify a state of polarization of an optical signal, a PDL emulator disposed upstream of the first polarization controller and configured to output the compensating PDL upstream of the first polarization controller, and a second polarization controller disposed upstream of the PDL emulator and configured to modify a state of polarization of the optical signal upstream of the PDL emulator.

Abstract: A wavelength converter for LiDAR systems, such as automotive LiDAR, is disclosed. Implementation of the wavelength converter in LiDAR systems makes possible generation and modulation of laser light in the silicon response region, conversion of the laser light to an eye-safe wavelength for emission and reflection from a target, and efficient conversion of the wavelength of the laser light to the silicon response region. The wavelength converter may implement a single-loop counter-propagating wavelength conversion scheme which provides both up-conversion and down-conversion of the signal within the same loop. The wavelength conversion design also has the potential for vehicle-to-vehicle (V2V) communication to enable a combined LiDAR and V2V communication system.

Abstract: Disclosed are systems, methods, and structures for DSP-free coherent receiver architectures applicable for short-reach optical links. Operationally, a received optical signal is down-converted by mixing it with a local oscillator (LO) laser signal using a 90-degree hybrid followed by balanced photodiodes. Other receiver functions are performed using analog signal processing thereby avoiding power-hungry, high-speed analog-to-digital converters and high-speed digital signal processing. Carrier phase recovery is performed by an electrical phase-locked loop employing a multiplier-free phase estimator stage that—while designed for quaternary phase-shift keying signals—may be employed in designs exhibiting higher modulation formats. Since carrier phase recovery is performed in the electrical domain, LO laser frequency modulation or LO laser integration is not employed.

Abstract: This application provides a method that includes the step of receiving, by a first device in a first time domain position, first scheduling information. The first scheduling information includes first indication information sent by a network device, wherein the first indication information is used to indicate a first interval. The method further comprises sending, by the first device, second scheduling information including second indication information to a second device in a second time domain position, wherein the second indication information is used to indicate a second interval, which is the difference between the first interval and a third interval. The second scheduling information is used by the second device to determine the target time domain position used by the second device to determine a time domain resource used to send and/or receive data.

Abstract: Optical transmitters, receivers, and methods are described in an optical network. An optical transmitter comprises an encoder configured to receive an input data stream and to encode the input data stream into a signal. The signal is defined as a sequence of regular units, and a rotator is configured to receive each unit of the signal and to output, for each given input unit with an input state of polarization (SOP), a respective given output unit associated with an output SOP. The output SOP of the given output unit is different from a corresponding output SOP of each other output unit that is immediately adjacent to the given output unit. The output SOPs of the units in a transmitted signal may form an alternating pattern (or other repeating pattern), which may help to lower the average BER, in particular, due to forward error correction (FEC).

Abstract: A method performed by a first device is disclosed that includes sending a light of sight, LOS, determination request to a second device which communicates with the first device, wherein the LOS determination request includes an indication of a dual polarization procedure for Line of Sight (LOS), with the indication of the dual polarization procedure for LOS is used indicating that a same sequence of bits is sent at two polarizations to the same direction; a channel measurement for each of the two received sequences at the two polarizations is compared to determine whether a transmission between the first device and the second is LOS or NLOS.

Abstract: A skew adjustment method and a digital coherent receiver which can achieve skew adjustment without using a fixed pattern for skew detection are provided. A digital coherent receiver (100) includes: a chromatic dispersion adder (103) that adds chromatic dispersion to the optical multiplexed signal; a skew adjuster (201) that sets a quantity of skew adjustment for each of the plurality of channel signals obtained by detecting the optical multiplexed signal; and a skew controller (204) that is configured to, while monitoring signal quality of a reception signal obtained from the plurality of channel signals skew-adjusted, search for a quantity of skew adjustment at which the signal quality is made better.

Abstract: Image display apparatus and methods may use a single imaging element such as a digital mirror device (DMD) to spatially modulate plural color channels. A color channel may include a light steering element such as a phase modulator. Steered light from a light steering element may be combined with or replaced by additional light to better display bright images. These technologies may be provided together or applied individually.

Abstract: A method, transceiver, and system for monitoring performance of a fiber optic-based communication network and, in particular to determining contributing linear and nonlinear noise components, is disclosed. The method includes computing fast bit error rate of a received optical signal at a sampling time interval that is less than or equal to 100 microseconds (?secs), generating, over a time period, a bit error rate distribution data associated with the computed fast bit error rate, applying statistical measurements to the bit error rate distribution data to extract statistical attribute data of the bit error rate distribution data, processing the extracted statistical attribute data to separately determine nonlinear noise components and linear noise components that contribute to total noise levels, and changing a launch power associated with an optical signal to be transmitted in accordance with separately determined nonlinear noise components and linear noise components.

Abstract: To realize sampling (signal measurement) and analysis of a signal to be measured easily at low cost by capturing optical phase fluctuation even when low-speed sampling is carried out.

Abstract: A method for dual polarisation optical transmission is disclosed. The method comprises splitting a continuous wave light source into first and second sub-channels, optically modulating each sub-channel with a data signal, and superimposing a first pilot tone onto the first optically modulated sub-channel and a second pilot tone, different from the first pilot tone, onto the second optically modulated sub-channel. The method further comprises polarisation multiplexing the first and second sub-channels to form a polarisation multiplexed signal, in which the first and second sub-channels have orthogonal states of polarisation, and transmitting the polarisation multiplexed signal.

Abstract: An optical receiver is provided with: an optical reception circuit which receives wavelength multiplexed light including signal light, converts the signal light into an electrical signal by coherent detection of the signal light using local oscillation light, and outputs the power of the local oscillation light, the bit error rate of the signal light and the electrical signal; and a controller which monitors the power of the local oscillation light and the bit error rate, calculates the signal-to-noise ratio of the signal light on the basis of the power of the local oscillation light and the bit error rate, and finds the number of wavelengths of the wavelength multiplexed light and the power per wavelength of the signal light on the basis of the signal-to-noise ratio and the power of the local oscillation light.

Abstract: A hyperspectral Raman imaging system having the ability to focus on excitation laser beam over a relatively wide field of view due to the use of a lens array, in particular a microlens array. Hyperspectral selection is provided in one embodiment through the use of dual-axis controlled dielectric filtration. Methods for analyzing materials with the system are disclosed. The device or system can be used in generally any application where investigation of materials is required.

Abstract: A data transmission method, device, and system includes, when a preset condition is met, determining a quantity N of first symbols included in one first symbol group and a quantity K of bits transmitted in the first symbol group, where the preset condition is ? log2 mN?>N·? log2 m?, K=? log2 mN?, m?2, N?2, and K?3; obtaining X data blocks, where each of the first X?1 data blocks includes K bits, the last data block includes Y bits, X?1, and K?Y?1; and processing each of the X data blocks into N first symbols to obtain NX first symbols, and sending the NX first symbols.

Abstract: The present invention discloses a method for measuring a spatial rotation angle of an object, comprising steps of: controlling projection of probe light onto an object whose rotation angle is to be measured; controlling a balance homodyne detector, by which the probe light reflected or transmitted by the object whose rotation angle is to be measured is detected to obtain light parameters of the reflected or transmitted probe light; and calculating a rotation angle of the object whose rotation angle is to be measured, according to the light parameters detected by the balance homodyne detector. The device of the present invention is simple, easy to operate, and high in practicality. The measurement precision is high, and measurements of a rotation angle beyond the SNL (shot noise limit) can be realized. The present invention can be applied in high-tech fields such as precise manufacturing, spatial remote-sensing and bioimaging.

Abstract: Consistent with an aspect of the present disclosure, electrical signals or digital subcarriers are generated in a DSP based on independent input data streams. Drive signals are generated based on the digital subcarriers, and such drive signals are applied to an optical modulator, including, for example, a Mach-Zehnder modulator. The optical modulator modulates light output from a laser based on the drive signals to supply optical subcarriers corresponding to the digital subcarriers. These optical subcarriers may be received by optical receivers provided at different locations in an optical communications network, where the optical subcarrier may be processed, and the input data stream associated with such optical subcarrier is output. Accordingly, instead of providing multiple lasers and modulators, for example, data is carried by individual subcarriers output from an optical source including one laser and modulator. Thus, a cost associated with the network may be reduced.

Abstract: An apparatus including first, second, third and fourth photodiodes, optical mixer and first and second optical power splitters. The optical mixer has two or more input ports, three output ports to output first, second and third mixtures of light corresponding to input light received from the input ports and transferred to the output ports. The first splitter has an input port and first and second output ports, to transmit part of one of the mixtures of light from one of the output ports to the first photodiode and a remaining part of the one mixture of light from the other one of the output ports to the third photodiode. The second splitter has an input port and first and second output ports, the second splitter to transmit part of another one of the mixtures of light from one of the output ports to the first photodiode and a remaining part of the other one of the mixtures of light from the other one of the output ports to the fourth photodiode.

Abstract: An optical chip comprises an input edge coupler having at least one input waveguide and configured to receive light on two orthogonal modes of same polarization, a demultiplexer configured to divide the two orthogonal modes into a mode carried on a first intermediate waveguide and a mode carried on a second intermediate waveguide independent from the first intermediate waveguide, a polarization multiplexer configured to recombine the modes carried on the intermediate waveguides into two polarization-orthogonal modes carried on one output waveguide.

Abstract: Fourier transform is performed on a reception signal to obtain a first calculation value. Fourier transform is performed on a known signal to obtain a second calculation value. The first calculation value is divided by the second calculation value to obtain a third calculation value. Inverse Fourier transform is performed on the third calculation value to obtain a fourth calculation value. A maximum value of an amplitude of the fourth calculation value and a sample point at which the maximum value is obtained are detected. The position of the known signal in the reception signal is detected from the sample point at which the maximum value is obtained.

Abstract: A method and device for optical data transmission are disclosed. Data bits are transmitted in the form of data symbols, by modulating an optical signal in dependence on the data bits and in accordance with two or more constellation schemes. The data bits are transmitted, by generating first data symbols, which represent respective sets of data bits containing an even number of data bits. The first data symbols are generated, by modulating the optical signal in accordance with a first constellation scheme. Furthermore, the data bits are transmitted, by generating second data symbols, which represent respective sets of data bits having an odd number of data bits. The second data symbols are generated, by modulating the optical signal in accordance with a second constellation scheme. The first and the second data symbols are generated at a predefined symbol rate, such that the first and the second data symbols are interleaved in time.

Abstract: Systems, methods, and computer-readable media for providing adaptive feedback in downhole telemetry in a wellbore. A feedback system includes a source assembly, which can be located on the surface or downhole, and a receiving assembly, which can likewise be located on the surface or downhole. The source assembly includes a source device that transmits a light signal having a first phase, and an encoder coupled to the source device. The receiving assembly comprising an oscillator that transmits an oscillator having a second phase, a coupler that couples the light signal with the oscillator signal, a detector and difference amplifier that detect and determine the difference between the first phase and second phase and a processor that receives the difference between the phases and provides the difference to an encoder so that the encoder can adjust the oscillator phase.

Abstract: A method of data symbol recovery in a coherent receiver of an optical communications system includes processing data symbol estimates detected from a received optical signal, and determining recovered symbol values from the processed data symbol estimates. The recovered symbol values belong to a symbol constellation having a predetermined asymmetry. Processing the data symbol estimates compensates phase noise that is greater than one decision region of the symbol constellation. A coherent receiver of an optical communications system includes a module configured to process data symbol estimates detected from a received optical signal and a decision circuit configured to determine recovered symbol values from the processed data symbol estimates. The recovered symbol values belong to a symbol constellation having a predetermined asymmetry. Processing the data symbol estimates compensates phase noise that is greater than one decision region of the symbol constellation.

Abstract: A distributed optical fiber disturbance positioning system based on the asymmetric dual Mach-Zehnder interference, unlike traditional dual Mach-Zehnder distributed optical fiber disturbance sensing system, the present invention adopts two narrow-bandwidth optical sources (1a, 1b) and adopts corresponding DWDM (3a, 3b) before the detector (4a, 4b) to filter the backscatter noise of the optical fiber, and can solve the problems of having too low SNR due to backscatter influence when the sensing distance is long. The present invention also provides a positioning method for applying the system, which obtains the TFD of the disturbance frame signals by using the time-frequency analysis method based on the short-term average frequency, and takes the points near the point of maximum frequency as the effective signal segment for performing cross-correlation time delay estimation, thus obtaining the delay, and the disturbance position.

Abstract: A data processing method and an apparatus, where the method includes receiving m data streams using m receive ports respectively, where the m data streams include m×m data units, and the m×m data units form an m-order matrix A, keeping a location of one element in each row in the matrix A unchanged and moving remaining m?1 elements to remaining m?1 rows respectively in order to form an m-order matrix B, where a column number of each element in the remaining m?1 elements in the matrix A before the element is moved equals a column number of the element in the remaining m?1 elements in the matrix B after the element is moved, and sending using m transmit ports, the m×m elements in the matrix B to m different levels of a pulse amplitude modulation (PAM) circuit respectively for performing modulation.

Abstract: An optical IQ demodulator that does not require a power-consuming DSP is disclosed. A DC offset is added to one of the I and Q optical signal components at an IQ transmitter. After mixing with an LO signal and differential detection at the receiver, this DC offset results in a heterodyne-frequency tone in each of the quadrature detection channels of the receiver. The phase of this oscillation is recovered using a PLL circuit, which output is used to separate the transmitter I and Q channels for decoding thereof using conventional electronics.

Abstract: A method of assembling an optical module that recovers data by interfering signal light with local light is disclosed. The optical module provides a housing with a side to which a signal port and a local port are fixed, and an optical components having a light incident surface whose normal makes an angle ? except for 0° and 90° against the axis of the signal port. The method first adjusts a rotation of the assembling apparatus by (1) setting a tool on the apparatus, where the tool has a pair of sides parallel to each other and a reference side making the angle ? against one of the paired sides, and (2) facing the reference side toward the preset direction. Next, setting the housing on the apparatus in an attitude same with the tool and facing the optical component toward the preset direction above the housing, the process installs the optical component within the housing.

Abstract: An optical reception apparatus (1) of the present invention includes: a local oscillator (11) outputting local oscillation light (22); an optical mixer (12) receiving a multiplexed optical signal (21) and the local oscillation light, and selectively outputting an optical signal (23) corresponding to the wavelength of the local oscillation light from the multiplexed optical signal; a photoelectric converter (13) converting the optical signal (23) output from the optical mixer into an electric signal (24); a variable gain amplifier (15) amplifying the electric signal (24) to generate an output signal (25) whose output amplitude is amplified to a certain level; a gain control signal generating circuit (16) generating a gain control signal (26) for controlling the gain of the variable gain amplifier (15); and a monitor signal generating unit (17) generating a monitor signal (27) corresponding to the power of the optical signal (23) using the gain control signal (26).

Abstract: A transceiver having an improved transmitter optical signal to noise ratio, and methods of making and using the same.

Abstract: A receiver for fiber optic communications.

Abstract: An optical receiver includes a processor. The processor calculates first through fourth optical intensities that respectively indicate input optical intensities of in-phase component in the first polarization, quadrature component in the first polarization, in-phase component in the second polarization and quadrature component in the second polarization. The processor calculates polarization dependent intensity ratio and phase dependent intensity ratio based on the first through fourth optical intensities. The processor calculates an input optical intensity of a polarization multiplexed optical signal based on an optical intensity of one of the first through fourth amplifiers, the polarization dependent intensity ratio, and the phase dependent intensity ratio.

Abstract: A hyperspectral Raman imaging system having the ability to focus on excitation laser beam over a relatively wide field of view due to the use of a lens array, in particular a microlens array. Hyperspectral selection is provided in one embodiment through the use of dual-axis controlled dielectric filtration. Methods for analyzing materials with the system are disclosed. The device or system can be used in generally any application where investigation of materials is required.

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: A method of generating a signal being phase-shifted at a predetermined phase-shift division factor relative to a reference signal is disclosed. The method comprises: using the predetermined phase-shift division factor for selecting a modulation amplitude, modulating a control signal at the selected modulation amplitude, and combining the reference signal and the control signal to form the phase-shifted.

Abstract: A receiver device and receiving method for a coherent optical communication system are disclosed. The disclosed device includes: an optical splitter configured to split a received optical signal into at least two paths; a first amplifier configured to amplify a second optical signal from among a first optical signal and the second optical signal split into two paths; a second amplifier configured to amplify the output signal of the first amplifier; and a coherent receiver module configured to mix and detect the output signal of the second amplifier and the first optical signal. The disclosed device provides the advantages of suppressing the occurrence of frequency offsets and minimizing phase noise, as well as allowing manufacture with a low cost without requiring either an additional optical source or additional optical fibers.

Abstract: A digital signal processor (DSP) may include a receiver configured to receive an input signal. The DSP may include a processor component to perform carrier recovery on a set of digital signals representing a set of symbols associated with the input signal. The DSP may include an output component to provide information included in the set of digital signals representing the set of symbols. The DSP may be configured to perform, for the input signal, phase estimation with a latency of less than approximately 880 nanoseconds and having a power consumption of less than approximately 400 milliwatts at an update rate greater than approximately 4 Gigahertz. The latency being a propagation delay of the input signal.