In one embodiment, a method for passive optical network (PON) communication includes broadcasting, by an optical line terminal (OLT), a first message including a first start time of a first quiet window and a first allocation identification number (Alloc-ID), where the first Alloc-ID indicates a first supported upstream line rate associated with the first quiet window. The method also includes receiving, by the OLT from a first optical network unit (ONU) during the first quiet window, a first serial number response, wherein a first transmitting upstream line rate of the first ONU is equal to the first supported upstream line rate.

An optical transceiver and a network device are provided. The optical transceiver includes a common end module and two data submodules. The common end module includes a multi-carrier light source, a wavelength division multiplexer, a wavelength division demultiplexer, an external optical interface, and two first beam splitters. Each data submodule includes a second beam splitter, an optical/electrical signal modulator, and an optical receiver. According to the optical transceiver and the network device, a high-capacity optical transceiver with a single optical interface can be implemented, so that optical interface management complexity is reduced, and a fiber resource is reduced.

A computerized system and method for managing a passive optical network (PON) is disclosed. The system includes a detection and analysis module adapted for receiving uploaded measurement data from an optical line terminal (OLT) and at least one optical network terminal (ONT), and at least one of technical tools data, service failure data, and outside plant data. The detection and analysis module is adapted for determining a source of failure or potential failure in the PON by correlating the uploaded measurement data and the at least one of technical tools data and service failure data with information stored in a memory medium for the OLT and each ONT.

A distributed antenna system (DAS) includes a master unit; a plurality of remote units communicatively coupled with the master unit and distributed to provide coverage within a service area, each of the remote units remotely located from the master unit and other remote units; a coupler element coupled to receive a plurality of MIMO signals, the MIMO signals including first and second MIMO signals, the coupler element configured to: introduce a phase shift in a first portion of the first MIMO signal to generate a first phase shifted portion of the first MIMO signal; combine the first phase shifted portion with a second portion of the second MIMO signal to generate a combined MIMO signal; and present the combined MIMO signal at a first output port of the coupler element; at least one antenna coupled with each remote unit and configured to receive the combined MIMO signal for transmission.

An optical transceiver that installs an optical modulator with the Mach-Zehnder type and made of primarily semiconductor materials, and an Erbium Doped Fiber Amplifier (EDFA) is disclosed. The EDFA and the MZ modulator, in addition to a wavelength tunable laser diode, an intelligent coherent receiver, and a polarization maintaining splitter, are installed within a compact case following the standard of CFP2.

Embodiments of the present invention disclose a method and an apparatus for detecting an ONU, and a passive optical network system. The method includes detecting an identity code of an ONU in an open uplink empty window or an empty timeslot, and determining that an ONU corresponding to the identity code of the ONU is a rogue ONU according to the identity code of the ONU. A corresponding apparatus and passive optical network system are also provided in the embodiments of the present invention. In the passive optical network system, a rogue ONU is detected and determined quickly and efficiently, and an effect on an uplink service is reduced.

A bi-directional optical transceiver includes multiple single mode optical ports and a multi-mode optical port. A multi-mode optical combiner combines single mode optical signals received at the single mode optical ports into a multi-mode optical signal at the multi-mode optical port. Each single mode optical signal has a distinct optical mode that does not interfere with the optical mode of the other single mode optical signals. A photo detector detects a total optical power of the plurality of single mode optical signals in the multi-mode optical signal. An amplifier is coupled to receive an output of the photo detector.

A communication system includes a first multiplexer configured to multiplex a first optical line terminal signal having a first multiplexing group and a second optical line terminal signal having a second multiplexing group into a first multiplexed signal. The communication system includes a second multiplexer configured to demultiplex a second multiplexed signal into a third optical line terminal signal having the first multiplexing group and a fourth optical line terminal signal having the second multiplexing group. Moreover, the communication system includes a third multiplexer optically connected with the first multiplexer and the second multiplexer, the third multiplexer configured to multiplex/demultiplex between a feeder optical signal and the first and second multiplexed signals. The first and second optical line terminal signals include a legacy upstream free spectral range, and the third and fourth optical line terminal signals include a legacy downstream free spectral range.

An optical access network comprises an optical network unit having a first port for connecting to a first optical link, a second port for connecting to a second optical link and an optical source. The optical source is arranged to generate a first optical signal, to transmit the first optical signal via the first port, to receive an optical seed signal via the first port and to amplify the optical seed signal. The optical seed signal has a narrower bandwidth compared to the first optical signal. A modulator is arranged to modulate the amplified optical seed signal with upstream data to form an upstream optical signal and to transmit the upstream optical signal via the second port. A polarisation modifier can modify polarisation of the first optical signal.

A system for communicating data signals over an optical transmission path combines forward signals onto a fiber that also carriers return signals. The system includes a return receiver for detecting an optical beat interference (OBI) event. Return signals are received by return receivers, one for each group of users. The fiber is provided to a splitter that distributes the forward optical receivers to the end users (RTx), which each comprise a receiver for the forward wavelength and a transmitter for the return wavelength. The transmitters provide return signals. When multiple transmitters are on at the same time, OBI events can take place when transmitter wavelengths coincide. When the return receiver detects an OBI event, it may signal the end user devices via a forward communication. The end user devices are responsive to the OBI detection signal to adjust a return wavelength to reduce or eliminate OBI.