An optical line terminal (OLT) accumulates and stores a user frame for each physical layer identifier (PLID) to efficiently use a plurality of lanes used for downstream transmission from the OLT to an optical network unit (ONU). The OLT envelopes payloads that are accumulatively stored for the respective PLIDs based on a transmission rate supported by a corresponding ONU, combines an envelope header based on an envelope payload unit, and transmits an envelope frame. The OLT selects an available lane from among a plurality of lanes and may transmit the envelope frame through the selected lane.

An optical transmission system in which a transmitting station and a plurality of receiving stations are connected via an optical splitter, wherein the transmitting station includes: a controller configured to determine whether to perform intensity modulation or phase modulation on optical signals based on information on transmission distances to the receiving stations and modulation bands; an intensity modulator configured to perform intensity modulation on an optical signal; and a phase modulator configured to perform phase modulation on an optical signal, and wherein one of an intensity modulation signal and a phase modulation signal is transmitted from the transmitting station to each of the receiving stations.

An apparatus for transmitting optical signals between a central unit (1) and at least one remote unit (2), said central unit comprisingat least one amplified spontaneous emission source (11, 110) of an optical signal, first means (17, 170) adapted to polarize the optical signal deriving from the amplified spontaneous emission source in a first polarization plane by forming a first polarized optical signal (POS). The apparatus comprises second means (24) configured to receive said first polarized optical signal and to polarize it in a second polarization plane, orthogonal to the first plane, by forming in said first means a second optical signal (SOS) which is orthogonally polarized with respect to the first optical signal (17).

A method of recovering a synchronization detection error according to an embodiment includes: determining whether a base station signal input to a head-end device is detected; determining whether a head-end signal output from the head-end device, which is obtained by processing the base station signal by the head-end device, is detected by a lower device of the head-end device; determining whether synchronization of the head-end signal is detected based on the head-end signal input to the lower device; and changing a set frequency band or performing automatic gain control of the head-end device based on whether the base station signal is detected, whether the head-end signal is detected, and whether the synchronization of the head-end signal is detected

Disclosed is an optical line terminal (OLT), including: N tunable modules, each of the N tunable modules include M tunable transmitters, the number of tuning channels of the M tunable transmitters is greater than or equal to two and the number of the tuning channels is less than MN, wherein N and M are integers greater than or equal to two.

The present disclosure provides a data transmission method and apparatus, a network device, a system, and a storage medium. The data transmission method includes: continuously sending downlink data frames of different rates at a first designated wavelength in a time-division multiplexing manner, with the downlink data frames carrying clock recovery information and time slot identification information of the downlink data frames of the different rates; and the clock recovery information is used for an optical network unit to perform clock recovery on the downlink data frames of the different rates, and the time slot identification information is configured to indicate time slot information of the downlink data frames of the different rates at the first designated wavelength.

In one embodiment, a first group of splitters receives a group of signals from a group of transmitters. Each splitter in the first group of splitters splits a signal into a plurality of signals that are sent to a plurality of multiplexers. A multiplexer in the plurality of multiplexers receives one of the plurality of signals from each splitter in the group of splitters and multiplexes the received one of the plurality of signals into a multiplexed signal. The multiplexer sends the multiplexed signal through a single connection in which upstream signals are sent to a group of nodes and downstream signals are received from the group of nodes. A de-multiplexer de-multiplexes the multiplexed signal into the group of signals and sends the group of signals to the group of nodes via a second group of splitters that are connected to the group of nodes.

Systems and methods for delivering multiple passive optical network services are disclosed. One system includes a first optical transmission service comprising a common wavelength pair routed from a source to each of a plurality of subscribers and a second optical transmission service comprising a plurality of unique wavelength pairs, each of the unique wavelength pairs assigned to a subscriber among the plurality of subscribers. The system includes a splitter optically connected to first fiber carrying the first optical transmission service, the splitter including a plurality of outputs each delivering the first optical transmission service, and a wavelength division multiplexer connected to a second fiber, the wavelength division multiplexer separating each of the unique wavelength pairs of the second optical transmission service onto separate optical fibers. The system further includes a plurality of second wavelength division multiplexers optically connected to a different output of the plurality of outputs of the splitter and to a different one of the unique wavelength pairs from the wavelength division multiplexer, thereby combining a unique wavelength pair and a common wavelength pair onto a single fiber to be delivered to a subscriber.

An optical line terminal (OLT) accumulates and stores a user frame for each physical layer identifier (PLID) to efficiently use a plurality of lanes used for downstream transmission from the OLT to an optical network unit (ONU). The OLT envelopes payloads that are accumulatively stored for the respective PLIDs based on a transmission rate supported by a corresponding ONU, combines an envelope header based on an envelope payload unit, and transmits an envelope frame. The OLT selects an available lane from among a plurality of lanes and may transmit the envelope frame through the selected lane.

Provided are a method and system for allocating wavelength channels in a Passive Optical Network (PON), and an Optical Line Terminal (OLT). In the method, an OLT may acquire pre-set wavelength channel priority information and Optical Network Unit (ONU) priority information; and the wavelength channel priority information and the ONU priority information may be sent to each ONU to enable each ONU to selectively access a corresponding wavelength channel according to the wavelength channel priority information and the ONU priority information based on a pre-set rule.