Optical network systems and components are disclosed, including a transmitter comprising a digital signal processor that receives data; circuitry that generate a plurality of electrical signals based on the data; a plurality of filters, each of which receiving a corresponding one of the plurality of electrical signals, a plurality of roll-off factors being associated with a respective one of the plurality of filters; a plurality of DACs that receive outputs from the digital signal processor, the outputs being indicative of outputs from the plurality of filters; a laser that supplies light; and a modulator that receives the light and outputs from the DACs, and supplies a plurality of optical subcarriers based on the outputs, such that one of the optical subcarriers has a frequency bandwidth that is wider than remaining ones of the optical subcarriers, said one of the optical subcarriers carrying information for clock recovery.

Optical network systems and components are disclosed, including a transmitter comprising a digital signal processor that receives data; circuitry that generate a plurality of electrical signals based on the data; a plurality of filters, each of which receiving a corresponding one of the plurality of electrical signals, a plurality of roll-off factors being associated with a respective one of the plurality of filters; a plurality of DACs that receive outputs from the digital signal processor, the outputs being indicative of outputs from the plurality of filters; a laser that supplies light; and a modulator that receives the light and outputs from the DACs, and supplies a plurality of optical subcarriers based on the outputs, such that one of the optical subcarriers has a frequency bandwidth that is wider than remaining ones of the optical subcarriers, said one of the optical subcarriers carrying information for clock recovery.

An optical transceiver includes a wavelength-tunable transmission unit configured to transmit an optical transmission signal, a wavelength-tunable reception unit configured to receive an optical reception signal, a wavelength table configured to store a plurality of combinations of a transmission wavelength and a reception wavelength, an input terminal configured to input a wavelength selection signal, and a control unit configured to select one combination of the transmission wavelength and the reception wavelength from the wavelength table based on the wavelength selection signal, and perform transmission wavelength control for setting the selected transmission wavelength in the wavelength-tunable transmission unit as a wavelength of the optical transmission signal and reception wavelength control for setting the selected reception wavelength in the wavelength-tunable reception unit as a wavelength of the optical reception signal.

A method in a first level aggregation node of a transport network is disclosed. The transport network comprises the first level aggregation node, a second level aggregation node and a Passive Optical Network. T the method comprises receiving, from the second level aggregation node, a plurality of wavelength division multiplexing (WDM) channels having wavelengths in a first spectrum section and generating at least one passive optical channel having a wavelength in a second spectrum section, different to the first spectrum section. The method further comprises combining at least some of the WDM channels received from the second level aggregation node with the at least one passive optical channel, and forwarding the combined WDM channels and passive optical channel to a termination node in the Passive Optical Network. Also disclosed are a method in a termination node of a transport network, a first level aggregation node, a termination node and a computer program.

A passive optical network includes a central office providing subscriber signals; a drop terminal; and a wave division multiplexer. A fiber distribution hub may split or separate out dedicated optical signals from subscriber optical signals between the central office and the drop terminal. The wave division multiplexer separates dedicated optical signals pertaining to a specific dedicated subscriber from other optical signals on the line received at the wave division multiplexer. The wave division multiplexer may be part of a cable or part of an intermediate service terminal.

An optical transmission system of an embodiment connects a plurality of wireless communication systems to each other, and includes a wavelength allocation unit that allocates different wavelengths to optical-terminating devices to which the wireless communication systems next to each other are connected, on the basis of the physical arrangement of each of the plurality of wireless communication system.

A system for delivering multiple passive optical network services is disclosed. The system includes a first optical transmission service comprising a common wavelength pair routed from a source to each of a plurality of subscribers. The system further includes a second optical transmission service comprising a plurality of unique wavelength pairs, where each of the unique wavelength pairs is routed from the source to a subscriber among the plurality of subscribers. The system delivers the first optical transmission service and the second optical transmission service to the subscriber on a single optical fiber.

A data processing method, a communications device, and a communications system, where in a process of transmitting a packet service, a code block stream carrying the packet service is first obtained, then, rate adaptation is performed on the obtained code block stream, and finally, the rate-adapted code block stream is mapped to an optical channel payload unit (OPU) signal. Compared with a mapping manner in which a Generic Framing Procedure (GFP) is used, the data processing method, the communications device, and the communications system feature low processing complexity and/or high bandwidth utilization.

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.

An optical transceiver includes a wavelength-tunable transmission unit configured to transmit an optical transmission signal, a wavelength-tunable reception unit configured to receive an optical reception signal, a wavelength table configured to store a plurality of combinations of a transmission wavelength and a reception wavelength, an input terminal configured to input a wavelength selection signal, and a control unit configured to select one combination of the transmission wavelength and the reception wavelength from the wavelength table based on the wavelength selection signal, and perform transmission wavelength control for setting the selected transmission wavelength in the wavelength-tunable transmission unit as a wavelength of the optical transmission signal and reception wavelength control for setting the selected reception wavelength in the wavelength-tunable reception unit as a wavelength of the optical reception signal.