An optical receiver includes an APD that converts an input optical signal into a current signal, a TIA that converts the current signal output from the APD into a voltage signal, an LIA that shapes a waveform of the voltage signal output from the TIA, an AOC having a time constant switching function, the AOC automatically compensating for an offset voltage between differential outputs from the TIA, and a convergence-state detection circuit that outputs, after detecting convergence completion of the automatic compensation in the AOC, to the AOC, a time constant switching control signal for switching a time constant from a high-speed time constant to a low-speed time constant.

A coherent frequency modulated receiver for receiving and detecting arriving optical signals which comprises an electrically controllable optical beam scanner receiving optical input beams arriving at different angles in a field of view of the electrically controllable optical beam scanner, the electrically controllable optical beam scanner conveying a scanned optical input beam as its output optical beam; a grating coupler responsive to the output or reflected optical beam of the electrically controllable optical beams scanner, the grating coupler having a waveguided output; an optical local oscillator laser having a waveguided output; an FMCW signal generator; an optical modulator responsive to the optical waveguided outputs of the optical local oscillator laser and also to an electrical FMCW signal from the FMCW signal generator; a pair of second order non-linear optical elements for frequency upconverting respective outputs of the optical modulator and the grating coupler; and at least one photodiode optically coupled to an outputs of the pair of second order non-linear optical elements.

The reception (102) reception unit includes; a first processing unit processing a first signal received from a source channel, and including a filtering unit to filter said first signal in digital domain, and extract unit to extract a information from said first signal; a second processing unit processing a second signal received from a destination channel, and said source channel and said destination channel are distinct each other; a third processing unit providing said information extracted from said first signal to said second signal said third processing unit executes; providing said information from said first processing unit to said second processing unit using information lanes of a clock rate strictly lower than a symbol rate of said second signal, a monitoring unit to generate a monitor signal according to the quality of said second signal; and a control unit controlling a skew between said first signal and said second signal in a bandwidth of said filtering units in said first processing unit.

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.

A device for coherent detection of data transported in an optical incoming useful signal. The device includes: a first incoming single-mode optical fibre, injecting the incoming useful signal; a second incoming single-mode optical fibre, injecting an optical signal of optical frequency substantially equal to that of the incoming useful signal, referred to as an oscillation signal, a signal mixer in which one of the signals from the first or second fibre is separated into two signals having orthogonal polarisations, and where the other one of the signals from the first or second fibre is mixed with the two separate signals, producing a mixed signal; a detector of the transported data present in the mixed signal; and an amplitude modulator configured to modulate the oscillation signal before it enters the mixer, the modulation pattern having repetitive pulses of the same interval as a symbol time of the incoming useful signal.

A method for performing optical constellation conversion, according to which each received symbol from a constellation of input symbols is optically split into M components and each component is multiplied by a first predetermined different complex weighing factor, to achieve M firstly weighted components with different amplitudes. Then a nonlinear processor optically performs a nonlinear transform on each M firstly weighted components, so as to obtain M outputs which are linearly independent, Finally, a linear processor optically performs a linear transform to obtain a new converted constellation by optically multiplying, in the complex plane, each of the M outputs by a second predetermined different complex weighing factor, to achieve M secondly weighted components and then summing the M secondly weighted components.

A coherent receiver comprising: a signal port receiving the signal light that has two polarization components at right angles each other; a polarization dependent beam splitter (PBS) that splits the signal light into two portions depending on the polarizations contained in the signal light; a beam splitter (BS) that splits the local light into two portions; a multi-mode interference (MMI) device that interferes between one of the two portions of the signal light and one of the two portions of the local light; optical components provided between the PBS and the MMI device; and wherein the PBS splitting a first wavelength range of the signal light and a second wavelength range outside the first wavelength range.

Embodiments of the present disclosure are directed toward techniques and apparatus comprising at least one layer of an ONN that includes an optical matrix multiplier provided in a semiconductor substrate to receive a plurality of optical signal inputs and to linearly transform the plurality of optical signal inputs into a plurality of optical signal outputs. The optical matrix multiplier comprises one or more 2×2 unitary optical matrices optically interconnected to implement a singular value decomposition (SVD) of a matrix, and a nonlinear optical device coupled with the optical matrix multiplier in the semiconductor substrate, to receive the optical signal outputs and to provide an optical output that is generated in a nonlinear manner in response to the optical signal outputs of the optical matrix multiplier reaching saturation or attenuation. Additional embodiments may be described and claimed.

A wavelength demultiplexer includes a photonic circuit and a control circuit that adjusts wavelength characteristics of the photonic circuit. The photonic circuit converts two orthogonal polarized waves contained in the incident light into two same polarized waves, which are supplied to a first optical demultiplexing circuit and a second optical demultiplexing circuit provided in the photonic circuit and having the same configuration. The photonic circuit supplies a total output power of monitor lights extracted from the same positions in the first optical demultiplexing circuit and the second optical demultiplexing circuit to the control circuit. The control circuit controls a first wavelength characteristic of the first optical demultiplexing circuit and a second wavelength characteristic of the second optical demultiplexing circuit based on the total output power of the monitor lights.

An optical assembly for optical signal processing: including a first input for coupling in a first light signal; a second input for coupling in a second light signal; a first beam splitter for splitting the first light signal into a first part and a second part; a second beam splitter for splitting the second light signal into a first part and a second part; a superposing unit; a detector; an electronic signal processing unit; at least one actuating unit; and a delay line for generating a delay of the running time of the first part of the first light signal and of the first part of the second light signal up to the superposing unit. The delay line is configured such that the first part of the first light signal and the first part of the second light signal pass through the delay line in opposite directions.