Pilot-aided digital coherent reception of high-order QAM signal detection using a continuous short pilot preamble and subsequent pilot symbols that are periodically distributed with payload data resulting in low-complexity and fast-convergence signal detection for continuous mode coherent reception of high-order QAM signals. A digital signal processor is configured to demodulate a transmitted data stream from digital stream of measurements of light mixtures produced in a receiver for coherent optical communications in response to receiving modulated optical carriers. The digital signal processor includes one circuit stage for providing corrections to the digital stream to compensate first effects on the light mixtures due to a frequency shift of a local optical oscillator of the receiver and another circuit stage for correcting the digital stream to compensate for second effects on the light mixtures due to polarization dependent channel modification of the modulated optical carriers.

Systems and methods for estimating a transmit symbol sequence implemented in a coherent receiver include receiving a nominally error-free information bit sequence subsequent to Forward Error Correction (FEC) decoding; determining a nominally error-free estimate of the transmitted bit sequence based on the nominally error-free information bit sequence; and determining a nominally error-free estimate of the transmit symbol sequence by mapping the transmit bit sequence to transmit symbols. The system and methods can further include comparing a transmit optical field based on the transmit symbols to a received optical field for one or more measurements.

The received signal strength of individual optical data bursts may be estimated based on the detection of bit patterns within each data burst associated with an amplifier recovery time period. The burst-by-burst estimates can be made faster than existing techniques.

The received signal strength of individual optical data bursts may be estimated based on the detection of bit patterns within each data burst associated with an amplifier recovery time period. The burst-by-burst estimates can be made faster than existing techniques.

In an optical communication system, an optical transmitter changes operational physical layer parameters to meet future target throughput for the optical communication system. The optical transmitter communicates the upcoming change to the optical receiver in a message that used current physical layer parameters. The optical transmitter provides sufficient time to the optical receiver to adjust reception functions of the receiver, including polarization based demodulation scheme. In some implementations, the optical transmitter performs the transition to a new physical layer transmission format without waiting for an acknowledgement from the optical receiver.

Provided are a method for processing an OS. The method includes: an OS sending node inserts OCh information into an overhead of an OMS of an OS; and/or, the OS sending node inserts the OCh information and optical carrier information into an OCh overhead of the OS, wherein the OCh information includes an identifier of the OCh, an NCF of an effective frequency slot of a media channel and a slot width of the effective frequency slot of the media channel, and a frequency slice granularity, and the optical carrier information includes: the number of optical carriers in the media channel, bit rates of the optical carriers in the media channel, modulation formats of the optical carriers in the media channel, NCFs of the optical carriers in the media channel, slot widths of the optical carriers in the media channel and a multiplexing method for the optical carriers.

A method, device and system for detecting optical signal are provided. The method includes that: an optical signal receiving node receives, from an optical signal sending node, an optical channel signal and the in-band overhead information of the optical channel signal; the optical signal receiving node carries out a misconnection detection on the optical channel signal according to the in-band overhead information and generates corresponding alarm information after determining that there is a misconnection, wherein an OCh TTI and Optical channel signal normal central frequency are carried in the in-band overhead information. The disclosure addresses the problem of how to effectively detect the misconnection of optical fibers after coherent reception technologies, including flexible grid, inverse multiplexing and optical devices, are introduced into related technologies and improves the optical signal receiving accuracy and the error detection and correction capability of a system.

A transmission device includes: a code generator configured to generate delay measurement information; an insertion unit configured to sequentially insert the delay measurement information generated by the code generator, in each of delay measurement signals in a plurality of frames, and to sequentially transmit the plurality of frames sequentially inserted with the delay measurement information to a counterpart device on a transmission path whose path delay time is to be measured; and a detector configured to receive a plurality of frames transmitted from the counterpart device and to detect the delay measurement information included in each of delay measurement signals in the plurality of received frames.

An optical frame is received over an optical link within an optical network. The optical frame contains a payload of aggregated data, an alignment value, and a bit interleaved parity value. The content of the optical frame is aligned based on the alignment value. The bit interleaved parity value is monitored. In response to the monitoring, a transmission quality of the transmission link is determined.

A transmission apparatus includes: a data signal processor to add first data of a control signal to a data signal received, and transmit the data signal; a first signal output module to output second data of the control signal; an update controller to control an update of a function included in the first signal output module; and a second signal output module, when receiving a notice of an instruction for updating the function from the update controller, to output the first data that is the second data held therein when the notice thereof is received, wherein the second signal output module, when receiving a notice of a completion for updating the function from the update controller, outputs the first data that is the second data received from the first signal output module updated by the update controller.