A method of controlling a wavelength of a wavelength tunable laser module includes: referring to data of measured frequencies and wavelength filter control values at two or more points for each basic frequency channel, the data being stored in a memory of a controller; selecting the basic frequency channel closest to a frequency of laser light that a laser light source is instructed to emit; calculating a first wavelength filter control value for providing the instructed frequency of laser light from the data of the measured frequencies allocated to the basic frequency channel closest to the instructed frequency and the wavelength filter control values; and controlling the transmission characteristic of a wavelength filter using the first wavelength filter control value.

An optical network communication system includes an optical hub, an optical distribution center, at least one fiber segment, and at least two end users. The optical hub includes an intelligent configuration unit configured to monitor and multiplex at least two different optical signals into a single multiplexed heterogeneous signal. The optical distribution center is configured to individually separate the at least two different optical signals from the multiplexed heterogeneous signal. The at least one fiber segment connects the optical hub and the optical distribution center, and is configured to receive the multiplexed heterogeneous signal from the optical hub and distribute the multiplexed heterogeneous signal to the optical distribution center. The at least two end users each include a downstream receiver configured to receive one of the respective separated optical signals from the optical distribution center.

Embodiments of the present disclosure provide a passive optical network communications method and apparatus, and a system. The method includes: determining a wavelength channel group of an optical network unit (ONU) and a wavelength channel in the wavelength channel group; and sending a first message to the ONU, where the first message carries identification information of the wavelength channel group and identification information of the wavelength channel in the wavelength channel group. In the embodiments of the present disclosure, such a logical channel group as a wavelength channel group is established, and when a channel in a channel group is faulty, a scheduling module of an OLT can rapidly and easily reallocate a service to another member in the channel group, so that channel interaction is avoided. Therefore, bandwidth scheduling efficiency and bandwidth utilization of a PON system are higher.

In a Fibre channel (FC) networking system, a first FC networking device includes a first Ethernet switch processor and a first FC PHY converter that is communicatively coupled to the first Ethernet switch processor via a first plurality of Ethernet links, where the first plurality of Ethernet links is grouped as a first Ethernet aggregation interface. A second FC networking device is communicatively coupled to the first FC networking device via a plurality of FC links, where each Ethernet link of the first plurality of Ethernet links is mapped to a corresponding FC link of the plurality of FC links. The first FC networking device is configured to: generate only one FLOGI for a FC trunk associated with the first Ethernet aggregation interface; and hash the FLOGI among the first plurality of Ethernet links so as to the second FC networking device via the first Ethernet aggregation interface.

A digital mobile fronthaul (MFH) network includes a baseband processing unit (BBU) having a digitization interface configured to digitize, using delta-sigma digitization, at least one wireless service for at least one radio access technology. The network further includes a transport medium in operable communication with the BBU. The transport medium is configured to transmit a delta-sigma digitized wireless service from the BBU. The network further includes a remote radio head (RRH) configured to operably receive the delta-sigma digitized wireless service from the BBU over the transport medium.

A system and method for performing an in-service optical time domain reflectometry test, an in-service insertion loss test, and an in-service optical frequency domain reflectometry test using a same wavelength as the network communications for point-to-point or point-to-multipoint optical fiber networks while maintaining continuity of network communications are disclosed.

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 transmission device includes a symbol generator that generates a modulation symbol by mapping transmission data to a signal point arranged in a two-dimensional or three-dimensional color space; and an outputter that outputs an optical signal modulated according to the modulation symbol.

A system and method for performing an in-service optical time domain reflectometry test, an in-service insertion loss test, and an in-service optical frequency domain reflectometry test using a same wavelength as the network communications for point-to-point or point-to-multipoint optical fiber networks while maintaining continuity of network communications are disclosed.

Consistent with the present disclosure, an encoder circuit is provided at a transmit side of an optical fiber link that maps an input sequence of bits of fixed length k a sequence of symbols of a codeword of length n, such that the symbols of the codeword define a predetermined transmission probability distribution. Preferably, each symbol of the codeword is generated during a corresponding clock cycle, such that after n clock cycles, a complete codeword corresponding to the input bit sequence is output. On a receive end of the link, a decoder is provided that outputs the k-bit sequence every n clock cycles. Accordingly, buffers need not be provided at the output of the encoder and the input of the decoder, such that processing of the input sequence, codewords, and output sequence may be achieved efficiently without large buffers and complicated circuitry. Moreover, the input sequence, with any binary alphabet may be matched to a desired output distribution with any arbitrary alphabet. Accordingly, probabilistic constellation shaping may be achieved over constellations of arbitrary size. In addition, relatively long codewords, may be encoded and decoded with the apparatus and method disclosed herein. Accordingly, for a fixed SNR a higher SE (more bits per symbol) can be achieved. Alternatively, for a fixed SE, a lower SNR may be sufficient. Moreover, the resulting SE may be finely tailored to a particular optical link SNR to provide data transmission rates that are higher than the low order modulation formats that would otherwise be employed for optical signals carried by such links.