A system and method of creating frames comprised of blocks, where each block comprises data symbols corresponding to a higher order quadrature modulation format and support symbols corresponding to a lower order modulation format. One or more of the blocks can further comprise markers comprising distinct symbol patterns. The markers can mark the start of each frame and/or another location in the frame. The support symbols can be in a common location in each block.

An apparatus comprises: a processor configured to: select a first channel from among a plurality of channels in a network, and generate a first message assigning a first grant corresponding to the first channel; a transmitter coupled to the processor and configured to transmit the first message; and a receiver coupled to the processor and configured to receive a second message on the first channel and in response to the first message. A method comprises: selecting a first channel from among a plurality of channels in a network; generating a first message assigning a first grant corresponding to the first channel; transmitting the first message; and receiving a second message on the first channel in response to the first message.

Provided is an optical transceiver including: a receiver configured to receive an optical transmission signal including wavelength information from another optical transceiver through a multiplexer/demultiplexer connected to the receiver; and a controller configured to identify a reception wavelength for communication with the other optical transceiver and to determine a wavelength corresponding to the reception wavelength as a transmission wavelength for communication with the other optical transceiver, based on the wavelength information included in the optical transmission signal.

A method and apparatus for communications in a passive optical network (PON) system are provided. An optical line terminal (OLT) generates a PON downstream Physical Layer (PHY) frame comprising a downstream physical synchronization block (PSBd) that comprises a wavelength identification (ID) of at least one downstream wavelength of the plurality of downstream wavelengths. The OLT sends the PON PHY frame comprising the wavelength ID in the PSBd to ONU for confirming the at least one downstream wavelength.

A system and method of creating frames comprised of blocks, where each block comprises data symbols corresponding to a higher order quadrature modulation format and support symbols corresponding to a lower order modulation format. One or more of the blocks can further comprise markers comprising distinct symbol patterns. The markers can mark the start of each frame and/or another location in the frame. The support symbols can be in a common location in each block.

In one embodiment, a method includes receiving, by a network controller and from a first node of a network, information associated with a data stream of the network and determining, by the network controller, a segmentation for the data stream. The segmentation includes a plurality of data segments and the plurality of data segments includes a first data segment. The method further includes determining, by the network controller, a data flow path for each of the plurality of data segments and determining, by the network controller, a first wavelength to assign to the first data segment. The first wavelength is one of a plurality of wavelengths spanning between the first node and a second node of the network.

In order to identify occupied bands in an optical transmitter with high accuracy, a band identifying circuit includes an optical intensity controller configured to change, by a prescribed level, an optical intensity of an optical signal outputted from a target-of-identification optical transmitter among a plurality of optical signals respectively outputted from a plurality of optical transmitters, constituting a wavelength-multiplexed optical signal, and having mutually different wavelengths, a spectrum acquisition circuit configured to measure an optical intensity of each wavelength of the wavelength-multiplexed optical signal and output a result of the measurement as a spectrum, and a band identifier configured to identify a band occupied by the target-of-identification optical transmitter, based on a change amount of the outputted spectrum.

According to an aspect of the present invention, an optical communication device includes: a detection unit that is connected to a user device and detects light which is output from the connected user device; a connection unit that connects the user device and a control transceiver in a case where light is detected by the detection unit; an acquisition unit that acquires, via the control transceiver, communication destination information indicating a communication destination to which the user device requests connection; an assignment unit that assigns a wavelength to the user device according to the communication destination information acquired by the acquisition unit; and a notification unit that notifies the user device of wavelength information indicating the wavelength assigned by the assignment unit via the control transceiver.

In some embodiments, an apparatus includes a first optical transceiver. The first optical transceiver includes a set of optical transmitters, an optical multiplexer operatively coupled to the set of optical transmitters, and a variable optical attenuator operatively coupled to the optical multiplexer. The variable optical attenuator is configured to receive a control signal from a controller of the first optical transceiver and modulate a signal representing control information with an output from the optical multiplexer. The control information is associated with the control signal and for a second optical transceiver operatively coupled to the first optical transceiver.

A method and apparatus for communications in a passive optical network (PON) system are provided. An optical line terminal (OLT) generates a PON downstream Physical Layer (PHY) frame comprising a downstream physical synchronization block (PSBd) that comprises a wavelength identification (ID) of at least one downstream wavelength of the plurality of downstream wavelengths. The OLT sends the PON PHY frame comprising the wavelength ID in the PSBd to ONU for confirming the at least one downstream wavelength.