Chromatic dispersion compensation is performed in one or more pluggable optical transceiver (POT) devices operating within an intensity-modulated direct-detection (IMDD) optical network. Compensation is performed within each POT using an electrical and/or optical chromatic dispersion module which are controlled by a set of parameters. A network computing device includes a computer processor and a host management interface for communicating with the POT. In the event of a link failure, the computer processor determines a second set of parameters to control the one or more dispersion compensation module(s) of the POT. The second set of parameters are different from a first set of parameters used to control the one or more compensation module(s) in the case of a first optical path. The computer processor causes the POT to use the second set of parameters in place of the first set of parameters.

An apparatus for determining a wavelength and a power of an input signal is described. The apparatus comprises a memory which stores instructions, which when executed by the processor, cause the processor to: recover a first phase for a first Mach-Zehnder Interferometer MZI; recover a second phase for a second MZI; subtract the first phase from the second phase to provide a phase difference; determine an unwrapped phase difference as a function of wavelength; determine a coarse wavelength; and determine a first wavelength for the first FSR and a second wavelength from the second FSR; and average the first and second wavelengths to determine the wavelength of the input signal.

An optical transmission system according to an embodiment includes: an optical transmission unit which modulates an optical signal into which a known signal is inserted and transmits the optical signal; and an optical reception unit which receives the optical signal from the optical transmission unit, wherein the optical reception unit includes: an optical receiver which performs coherent detection of a reception signal of the optical signal received from the optical transmission unit; a receiver transfer function estimation section which estimates a nonlinear response transfer function of the optical receiver based on the known signal included in the reception signal after the detection by the optical receiver; and a receiver compensation section which compensates nonlinear distortion of the reception signal after the detection based on the nonlinear response transfer function which the receiver transfer function estimation section estimates.

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.

A wavelength conversion device includes: a memory; and a processor configured to: receive transmission signal light in which first wavelength division multiplexing signal light and second wavelength division multiplexing signal light that have different wavelength bands in which a plurality of rays of main signal light is wavelength-multiplexed are combined with supervisory control signal light that relates to supervisory control of the first wavelength division multiplexing signal light and the second wavelength division multiplexing signal light from a transmission line and that demultiplexes the supervisory control signal light from the transmission signal light; detect input power of the supervisory control signal light; demultiplexer each of the first wavelength division multiplexing signal light and the second wavelength division multiplexing signal light from the transmission signal light; convert at least one of the wavelength bands of the first wavelength division multiplexing signal light and the second wavelength division multiplexing signal light.

A method for signal reconstruction, the method may include obtaining, an input digital signal that is a digital representation of an received optical signal, wherein the received optical signal represents a transmitted optical signal that was transmitted by a coherent transmitter and over a channel to a coherent optical receiver; wherein a phase difference between the transmitted optical signal and the received optical signal is unknown; and generating a hybrid estimation, wherein the hybrid estimation represents a magnitude of the transmitted optical signal and a phase of the received optical signal.

An optical assembly is used for communicating laser light from a plurality of laser sources into channels for an optical network. The optical assembly comprises an optical substrate, an input optic, at least one Z-block, filters, at least one fiber collimator, and at least one delivery fiber. The input optic is disposed on the optical substrate and is configured to receive the laser light from the laser sources. The input optic is configured to collimate the laser light into a plurality of collimated laser beams. The at least one Z-block is disposed on the substrate and has an input surface and an output surface. The input surface has a plurality of filters disposed thereon, and the input surface is disposed at an angle of incidence relative to the collimated beams from the input optic. The output surface is disposed parallel to the input surface and can have at least one isolator. The at least one Z-block is configured to multiplex the collimated laser beams into at least one output signal having a plurality of the channels. At least one fiber collimator disposed on the substrate has an input and an output. The input is disposed in optical communication with the at least one Z-block and is configured to receive the output signal. The at least one delivery fiber is optically coupled to the output of the at least one fiber collimator and is configured to conduct the optical signal to a receptacle.

A receiver is configured to extract a clock signal superimposed on a detection signal of light propagated to determine whether or not SNR of the detection signal is lower than SNR at which the detection signal can be demodulated; compensate a signal value of the detection signal by using a filter coefficient and output a detection signal after signal value compensation; and calculate, as the filter coefficient, a filter coefficient in which a signal value of a detection signal output from the adaptive filter is a reference value when it is determined that there is no SNR degradation, and changes the filter coefficient to a stored filter coefficient when it is determined that SNR degradation occurs.

Embodiments of this application disclose an optical switch. The optical switch includes at least one first port, at least one second port, a first wavelength division multiplexing WDM apparatus, an optical splitter, an optical monitoring apparatus, and an optical switching apparatus. The first port is configured to transmit an input first optical signal to the first WDM apparatus, where the first optical signal is a multi-wavelength signal. The first WDM apparatus is configured to demultiplex the first optical signal. The optical splitter is configured to split a demultiplexed first optical signal to obtain a first sub-signal and a second sub-signal. The optical switching apparatus is configured to perform optical switching on the first sub-signal. The second port is configured to output a first sub-signal obtained after optical switching. The optical monitoring apparatus is configured to perform optical performance monitoring on the second sub-signal.

A method is provided for assessing the quality of an optical transmitter and/or its interoperability with a receiver. The method includes obtaining an optical signal output by an optical transmitter and performing coherent optical-to-electrical detection of the optical signal to produce an in-phase receive signal and a quadrature receive signal. The method further includes a computing device emulating a worst-case configuration of an optical fiber with which the optical transmitter is to be used, based on the in-phase receive signal and the quadrature receive signal to produce a noise contribution associated with the worst-case characteristics of the optical fiber and determining a figure of merit of the optical transmitter based on the noise contribution.