A circuit board of the optical module comprises: a first electrical interface is configured to connect an electrical interface of a board or a second electrical interface of another optical module, and a second electrical interface is configured to connect a first electrical interface of another optical module; a first optical port is configured to connect an optical transmission device or a second optical port of another optical module, and a second optical port is configured to connect an optical receiving device or a first optical port of another optical module; and a optical transceiver assembly multiplexes downstream light and demultiplexes upstream light. The optical module provided in solutions of the present invention can be flexibly combined with another optical module, enabling flexible and gradual upgrade of an optical module bandwidth according to a user requirement by using various combination manners.

This application provides a port detection method, an optical network device, and a passive optical network system, to quickly and accurately detect a port connected to an ONU, and improve efficiency of determining the port connected to the ONU. The method includes: an optical line terminal sends optical signals corresponding to all of N wavelengths to at least one optical network unit, where the N wavelengths are different from each other, and N is a positive integer; the OLT receives optical power values that are of the optical signals corresponding to all of the N wavelengths and that are sent by a first ONU, where the first ONU is any one of the at least one ONU; and the OLT determines, bases on the optical power values of the optical signals corresponding to all of the N wavelengths, information about an optical splitter port corresponding to the first ONU.

In one embodiment, an apparatus is configured to perform mapping an interleaved bit stream into a sequence of 4-level pulse amplitude modulation (PAM4) labels according to a mapping scheme, with a respective PAM4 label including a least significant bit (LSB) and a most significant bit (MSB) respectively corresponding to a bit in the interleaved bit stream; transmitting a sequence of PAM4 symbols generated based on the sequence of PAM4 labels to the ONUs; and wherein, bits from respective one of the N codewords are assigned to LSBs of a first subset of labels, and to MSBs of a second subset of labels, with the first and the second subset of labels being determined based on the interleaving scheme and the mapping scheme and respectively comprising labels located N labels apart in the sequence of PAM4 labels.

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.

This application discloses a bandwidth allocation method, an optical line terminal (OLT), an optical network unit (ONU), and a system, where the method includes receiving a bandwidth request from each ONU, where the ONU includes an ONU1, generating a bandwidth map (BWMap) message according to bandwidth requested by the ONU and bandwidth configured by the ONU, where the BWMap message includes a first allocation identifier (Alloc-ID1), a first time corresponding to the Alloc-ID1, a second allocation identifier (Alloc-1D2), and a second time corresponding to the Alloc-ID2, and both the Alloc-ID1 and the Alloc-ID2 are allocated to the ONU1 for use, and sending the BWMap message to each ONU. Therefore, a problem that a transmission delay does not satisfy a requirement when a passive optical network (PON) system is applied to mobile backhaul is resolved, a data transmission rate and data transmission efficiency are improved, and user satisfaction is improved.

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).

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.

Methods and systems for reducing power consumption in a multi-channel passive optical network (PON). A processor in the PON may monitor the channels in the multi-channel PON to detect a currently inactive channel, determine whether the detected channel has been inactive for an extended period of time, and deactivate the detected channel (by deenergizing transmitter(s) and/or receiver(s) associated with the detected channel) in response to determining that the channel has remained inactive for an extended period of time. The processor may re-activate the channel in response to determining that an optical signal has been reliably present on the channel for a sufficient period of time.

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.

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.