An optical transmission apparatus includes an input unit, a demultiplexing unit, a measurement unit, and a switching unit. The input unit inputs a first multiplexed signal and a second multiplexed signal each obtained by multiplexing a plurality of optical signals having different wavelengths. The demultiplexing unit demultiplexes the first multiplexed signal and the second multiplexed signal by wavelength. The measurement unit measures qualities of a plurality of optical signals obtained by demultiplexing the first multiplexed signal and qualities of a plurality of optical signals obtained by demultiplexing the second multiplexed signal. The switching unit performs switching between the first multiplexed signal and the second multiplexed signal to be output to a subsequent stage based on a result of measurement by the measurement unit.

An optical transmission apparatus includes an input unit, a demultiplexing unit, a measurement unit, and a switching unit. The input unit inputs a first multiplexed signal and a second multiplexed signal each obtained by multiplexing a plurality of optical signals having different wavelengths. The demultiplexing unit demultiplexes the first multiplexed signal and the second multiplexed signal by wavelength. The measurement unit measures qualities of a plurality of optical signals obtained by demultiplexing the first multiplexed signal and qualities of a plurality of optical signals obtained by demultiplexing the second multiplexed signal. The switching unit performs switching between the first multiplexed signal and the second multiplexed signal to be output to a subsequent stage based on a result of measurement by the measurement unit.

This application discloses a communication system and method, and a related device. The communication system includes a CO device and a plurality of RRHs, where the plurality of RRHs constitute a ring network by using optical fibers; the CO device is connected to the ring network, and is configured to: modulate a baseband signal to N first optical carriers that are generated by the CO device, to obtain N second optical carriers; and transmit the N second optical carriers to the ring network by using a first optical fiber. Any RRH of the plurality of RRHs is configured to: obtain a target optical carrier from received second optical carriers, convert the target optical carrier into an electrical signal, and transmit the electrical signal as a downlink signal.

Disclosed is an optical network system including a upper network equipment, a lower network equipment, and a plurality of transfer network equipments connecting the upper network equipment and the lower network equipment through independent optical links, wherein the lower network equipment performs switching such that transmission and reception of an optical signal are performed through an optical link of a standby line when a failure occurs in at least one of an optical link used as a working line, an optical interface device associated with the working line in the upper network equipment, and a transfer network equipment associated with the working line.

Disclosed is an optical network system including a upper network equipment, a lower network equipment, and a plurality of transfer network equipments connecting the upper network equipment and the lower network equipment through independent optical links, wherein the lower network equipment performs switching such that transmission and reception of an optical signal are performed through an optical link of a standby line when a failure occurs in at least one of an optical link used as a working line, an optical interface device associated with the working line in the upper network equipment, and a transfer network equipment associated with the working line.

Apparatus for enabling an M:N recovery scheme in an optical network includes a set of N working DSP-enabled optical transceivers/transponders including at least one working DSP-enabled optical transceiver/transponder that uses a first set of transmission parameters and at least one working DSP-enabled optical transceiver/transponder that uses a second set of transmission parameters which is different from the first set of transmission parameters, and a set of M protection DSP-enabled optical transceivers/transponders operable to protect the set of N working DSP-enabled optical transceivers/transponders and including L protection DSP-enabled optical transceivers/transponders, each having a capability of using a set of adjustable transmission parameters enabling it to protect every one of the N working DSP-enabled optical transceivers/transponders, and, when M>L, M-L protection DSP-enabled optical transceivers/transponders, each having a capability of protecting at least one, but not all, of the N working DSP-enabled optical transceivers/transponders. Related network and methods are also disclosed.

Apparatus for enabling an M:N recovery scheme in an optical network includes a set of N working DSP-enabled optical transceivers/transponders including at least one working DSP-enabled optical transceiver/transponder that uses a first set of transmission parameters and at least one working DSP-enabled optical transceiver/transponder that uses a second set of transmission parameters which is different from the first set of transmission parameters, and a set of M protection DSP-enabled optical transceivers/transponders operable to protect the set of N working DSP-enabled optical transceivers/transponders and including L protection DSP-enabled optical transceivers/transponders, each having a capability of using a set of adjustable transmission parameters enabling it to protect every one of the N working DSP-enabled optical transceivers/transponders, and, when M>L, M-L protection DSP-enabled optical transceivers/transponders, each having a capability of protecting at least one, but not all, of the N working DSP-enabled optical transceivers/transponders. Related network and methods are also disclosed.

A method to avoid sympathetic switches in path switching protection due to client protection switching includes monitoring a drop side Tandem Connection Monitoring (TCM) entity and a line side TCM entity for a connection, wherein the drop side TCM is provisioned between a drop port of the node and a second drop port of a corresponding node, and wherein the line side TCM entity is provisioned between a plurality of line ports of the node and a second plurality of line ports of the corresponding node; responsive to detecting defects in both the drop side TCM entity and the line side TCM entity on a working line, implementing path protection switching of the working line; and, responsive to detecting defects only in the drop side TCM entity, implementing path protection switching of the working line responsive to persistence of the defects.

A method to avoid sympathetic switches in path switching protection due to client protection switching includes monitoring a drop side Tandem Connection Monitoring (TCM) entity and a line side TCM entity for a connection, wherein the drop side TCM is provisioned between a drop port of the node and a second drop port of a corresponding node, and wherein the line side TCM entity is provisioned between a plurality of line ports of the node and a second plurality of line ports of the corresponding node; responsive to detecting defects in both the drop side TCM entity and the line side TCM entity on a working line, implementing path protection switching of the working line; and, responsive to detecting defects only in the drop side TCM entity, implementing path protection switching of the working line responsive to persistence of the defects.

An optical transmitter includes photonic integrated circuits configured to respectively output optical transmission signals in different wavelength ranges. A photonic integrated circuit may include emitters configured to emit beams having different wavelengths; drivers configured to respectively provide power to the emitters, and a wavelength division multiplexer configured to transmit the beams emitted by the emitters. A photonic integrated circuit may include a switch device that controls the drivers, and light detectors configured to detect intensities of the beams emitted from the emitters. The switch device may selectively operate at least one driver of the plurality of drivers based on information associated with intensities of the beams. The switch device may selectively operate a driver connected to an emitter, based on a determination that an intensity of a beam emitted by another emitter is less than a threshold intensity value.