Example embodiments of a time division duplex (TDD) Wavelength Division Multiplex Passive Optical Network (WDM PON) architecture using passive optical splitters are disclosed herein. The disclosed TDD WDM PON includes fixed wavelength optical transmitters in an Optical Line Termination system with tunable receiver colorless Optical Network Units (ONUs) that reuse the downstream CW light to carry upstream data. The same wavelength may be used for downstream and upstream transmissions on a single fiber in the ODN. In this architecture, the number of ONUs may be greater than the number of transmitters at the OLT, allowing for a highly scalable system with capacity for growth. An example embodiment of the disclosed system uses Arrayed Waveguide Grating (AWG) or WDM filters at the OLT and a passive optical splitter in the field.

The station-side terminal apparatus for the optical access network includes: the station-side terminal apparatus; the subscriber-side terminal apparatuses connected to the station-side terminal apparatus via the optical transmission line; the terminal devices to which mutually different wavelengths are assigned; and the communication failure detecting unit. Each of the terminal devices includes the uplink communication state monitoring unit configured to monitor a state of uplink communication for each registered subscriber-side terminal apparatus, on the basis of the input uplink signal, and the downlink communication failure information extracting unit configured to extract information of a state of downlink communication, which is transmitted from the registered subscriber-side terminal apparatus. The communication failure detecting unit detects a failure of the uplink communication and a failure of the downlink communication, on the basis of the state of the uplink communication and the state of the downlink communication.

Proposed is a method of receiving a WDM optical upstream signal in an optical access network. The WDM signal is filtered using a first optical filter yielding a first filtered signal. The first optical filter has a flat-top shaped pass-band transfer function. Furthermore the WDM signal is filtered using second optical filter yielding a second filtered signal. The second optical filter has a pass-band transfer function that is strictly monotonically increasing for wavelength values below a center wavelength of the transfer function and that is strictly monotonically decreasing for wavelength values above the center wavelength of the transfer function. Received upstream data is derived from the first filtered signal. An optical signal power level is derived from the second filtered signal an optical signal power level. Finally, it is indicated to an optical network unit a desired direction of wavelength shift in dependence on the derives signal power level.

A network component comprising at least one processor configured to implement a method comprising collecting wavelength availability information associated with a wavelength switched optical network (WSON), receiving a path computation request to transport a signal through the WSON, calculating at least one route through the WSON for the signal, and assigning at least one wavelength for the signal to use along the route. Also disclosed is a network comprising a first path computation element (PCE) configured to compute at least one route for a signal between a source and a destination, and a second PCE in communication with the first PCE, wherein the second PCE is configured to receive the route from the first PCE and assign at least one wavelength to the route.

An extended cavity Fabry-Perot laser assembly provides relatively narrow mode spacing while allowing relatively high speed optical modulation. The extended cavity Fabry-Perot laser assembly generally includes an exit reflector physically separated from a laser emitter (e.g., a gain chip) to extend the lasing cavity and narrow the mode spacing while maintaining a relatively small gain region in the laser emitter capable of higher speed optical modulation. The extended cavity Fabry-Perot laser assembly may be used in a multi-channel transmitter in a wavelength division multiplexed (WDM) optical system that selects a channel wavelength for the transmitter from among multiple channel wavelengths emitted by the laser assembly. The narrow mode spacing may be less than a WDM channel width, and more specifically, may be less than a channel passband of an arrayed waveguide grating (AWG) or other filter used to select the channel wavelength.

An apparatus comprising a first tunable transmitter array comprising a first tunable transmitter and a second tunable transmitter and a cyclic array waveguide grating (AWG) wavelength router coupled to the first tunable transmitter array, wherein the cyclic AWG wavelength router comprises a plurality of input ports and a plurality of output ports, wherein the cyclic AWG wavelength router is configured to receive a first optical signal emitted from a first tunable transmitter via a first input port of the plurality of input ports, receive a second optical signal emitted from a second tunable transmitter via the first input port of the plurality of input ports, and route the first optical signal and the second optical signal to the output ports dependent on one or more wavelengths used to encode the first optical signal and the second optical signal.

A supervisory channel is provided on an optical path (31) between nodes of an optical communication network. The nodes are arranged to use a set of wavelengths allocated for carrying traffic channels. An optical signal (16) which carries a supervisory channel is generated at a supervisory channel transmitter (15) and added (12) to the optical path (31) downstream of an optical amplifier (11). The optical signal (16) has a wavelength which is one of the set of wavelengths allocated for carrying traffic. The method is performed at a time when the wavelength is not being used to carry traffic. An impairment parameter of the received optical signal is measured at a supervisory channel receiver (15). The receiver is a coherent receiver and the impairment parameter is chromatic dispersion or polarization mode dispersion.

The invention relates to a receiving device (Rx1_b) capable of receiving an optical signal emitted by an emitting device including a light source for emitting the optical signal, the optical signal being transmitted by a passive optical network having wavelength division multiplexing, the receiving device including: an optical amplifier (Amp_b) for amplifying the optical signal received from the emitting device; an optical detector (D_b) capable of detecting data in the amplified optical signal; an optical reflector (Ref_b) configured to return the amplified optical signal toward the emitting device, such as to tune the wavelength of the optical signal emitted by the emitting device by means of a round trip of the optical signal between the emitting device and the optical reflector.

Embodiments of this application provide an OLT, an ONU, and a system. In a downlink direction, the first OLT is configured to convert received downlink data packets of M1 paths into one downlink optical signal whose wavelength is o, and the first ONU is configured to receive the downlink optical signal, and output a target user data packet after processing the downlink optical signal. In an uplink direction, the first ONU is configured to convert received uplink data packets into an uplink optical signal whose wavelength is i, and the first OLT is configured to receive a plurality of uplink optical signals of different wavelengths, and output user data packets of a corresponding quantity of paths after processing.

A laser light generator is configured to generate one or more wavelengths of continuous wave laser light. The laser light generator is configured to collectively and simultaneously transmit each of the wavelengths of continuous wave laser light through an optical output of the laser light generator as a laser light supply. An optical fiber is connected to receive the laser light supply from the optical output of the laser light generator. An optical distribution network has an optical input connected to receive the laser light supply from the optical fiber. The optical distribution network is configured to transmit the laser light supply to each of one or more optical transceivers and/or optical sensors. The laser light generator is physically separate from each of the one or more optical transceivers and/or optical sensors.