A wavelength multiplexing communication system includes a master station apparatus and a plurality of slave station apparatuses. The master station apparatus includes a wavelength multiplexing communication unit. The wavelength multiplexing communication unit performs wavelength multiplexing communication with the plurality of slave station apparatuses by using optical signals having the number of wavelengths equal to or less than the number of the plurality of slave station apparatuses. The slave station apparatus includes an optical communication unit. When the main signal communication is performed in the host slave station apparatus, the optical communication unit communicates with the master station apparatus by an optical signal having the same wavelength as a wavelength used by another slave station apparatus in which a main signal notification is not performed.

Systems and methods for mapping optical connections in an FDH are disclosed. An example system includes an FDH and a computing device. The FDH includes a bulkhead having: a plurality of passive optical couplers each having a respective first port to receive a respective first optical fiber, a respective second port to receive a respective second optical fiber, and a respective passive optical activity indicator configured to expose first light propagating in the respective first optical fiber, and second light propagating in the respective second optical fiber; and an image sensor configured to capture one or more images of the plurality of passive optical activity indicators. The computing device configured to, based on the one or more images, determine which of the plurality of passive optical couplers are receiving a first optical signal at their respective first port and/or receiving a second optical signal at their respective second port.

This application provides a port detection method and apparatus. In the technical solutions in this application, an OLT or an ONU may determine, based on at least two wavelengths and a preset correspondence, port information that is of an optical splitter and that corresponds to the ONU. That is, a branch port directly or indirectly connected to the ONU is defined by using the at least two wavelengths. In this way, different branch ports can be distinguished by using combinations of a plurality of wavelengths, to define a large quantity of branch ports of the optical splitter by using free combinations of a small quantity of wavelengths.

An apparatus includes a TDM PON optical transceiver including a direct-detection optical receiver. The direct-detection optical receiver is configured to demodulate data from a temporal segment of a data modulated optical signal, wherein the optical carrier frequency of the segment varies at a rate of, at least, 1 giga-Hertz per second.

An optical communication system according to the present invention cancels waveform distortion due to wavelength dispersion by extracting the spectrum of a transmitted optical signal and passing the optical signal to a fiber having a dispersion value opposite to a dispersion amount corresponding to a transmission distance received by the spectrum component and compensates for a transmission path loss due to the fiber having the opposite dispersion value using optical splitters having different split ratios. With this configuration, the present invention can compensate for waveform distortion due to wavelength dispersion by a simple method in an access network and achieve an increase in the reachable transmission distance of the farthest user or an increase in the number of connectable users.

A method for increasing the capacity of a passive optical network. The passive optical network includes an existing multi-service terminal having a plurality of hardened fiber optic drop ports, and also includes an optical line terminal that provides service to the existing multi-service terminal. The method includes upgrading the optical line terminal to support at least 10GPON and to have increased launch power and enhanced loss sensitivity. The method also includes adding a passive optical splitter between the optical line terminal and the existing multi-service terminal, connecting the existing multi-service terminal to a first output of the passive optical splitter, and connecting an expansion multi-service terminal to a second output of the passive optical splitter.

In some examples, an optical time-domain reflectometer (OTDR)-based high reflective event measurement system may include an OTDR, and an N by M optical switch optically connected to the OTDR or disposed within the OTDR. The optical switch may include a variable attenuator mode and at least one optical fiber connected to at least one output port of the optical switch. At least one fiber optic reflector may be disposed at an end of the at least one optical fiber. A variable optical attenuator may reduce, for the at least one optical fiber including the at least one fiber optic reflector, an amplitude of reflective peaks.

Controller circuitry configured to control an optical transceiver of an optical line terminal, OLT, in a passive optical network, PON. The controller circuitry configured to derive a level of optical beat interference, OBI, of a received upstream optical signal from an optical transceiver of an optical network terminal, ONT; and set a wavelength of a downstream optical signal based on the level of OBI such that the wavelength is forced to differ from the upstream optical signal wavelength.

A method (900) includes a gain current (I.sub.GAIN) to an anode of a gain-section diode (D.sub.0) disposed on a shared substrate of a tunable laser (310), delivering a modulation signal to an anode of an Electro-absorption section diode (D.sub.2) disposed on the shared substrate of the tunable laser, and receiving a burst mode signal (330) indicative of a burst-on state or a burst-off state. When the burst mode signal is indicative of the burst-off state, the method includes sinking a sink current (I.sub.SINK) away from the gain current at the anode of the gain-section diode. When the burst mode signal transitions to be indicative of the burst-on state from the burst-off state, the method includes ceasing the sinking of the sink current away from the gain current and delivering an overshoot current (I.sub.OVER) to the anode of the gain-section diode.

This application provides a training sequence determining method and a related device. The method in embodiments of this application includes: An ONU receives a first message sent by an OLT. Then, the ONU determines a target training sequence based on the first message, where the target training sequence is used to determine a working parameter of an equalizer in the OLT. Further, the ONU generates a first data frame including the target training sequence. In this application, the OLT may perform training based on the received target training sequence to determine the working parameter of the equalizer in the OLT.