An apparatus for management of a spectral capacity of a wavelength division multiplexing, WDM, system includes at least one pair of transmission fibers provided for transporting optical signals. Each transmission fiber of a transmission fiber pair is connected to a first port of an optical circulator having at least two additional ports and adapted to transmit an incoming optical signal entering one of its ports via its next port. WDM subsystems configured with counter-propagating assignable wavelengths are connected to associated ports of the optical circulator of the apparatus.

An optical transmitter can generate probabilistically shaped quadrature amplitude modulation (PS-QAM) signaling for transmission over a fiber to a destination without optical amplification. The single fiber can transmit the PS-QAM signaling using dense wavelength division multiplexing having a relatively large number of channels that are closely spaced. A coherent receiver can receive the PS-QAM signaling for decoding without implementing chromatic dispersion compensation.

A light source apparatus (200) includes a gas discharge stage (210) and a metal fluoride trap (300). The gas discharge stage includes an optical amplifier (206) and a set of optical elements (250, 260). The optical amplifier includes a chamber (211) configured to hold a gas discharge medium (213), the gas discharge medium outputting a light beam. The set of optical elements is configured to form an optical resonator around the optical amplifier. The metal fluoride trap is configured to trap metal fluoride dust generated from the gas discharge stage. The metal fluoride trap includes an electrostatic precipitator (320) and a packed-bed filter (400, 402, 404) disposed around the electrostatic precipitator. The packed-bed filter includes a plurality of beads configured (406, 408) to absorb metal fluoride dust (208).

An apparatus includes a reconfigurable optical add/drop multiplexer (ROADM) having an input port to receive a first optical signal from a second device. The ROADM also includes a first wavelength selective switch (WSS), in optical communication with the input port, to convert the first optical signal into a second optical signal, a loopback, in optical communication with the first WSS, to transmit the second optical signal, and a second WSS, in optical communication with the loopback, to convert the second optical signal to a third optical signal and direct the third optical signal back to the second device via the input port.

A method for establishing an embedded optical communication channel in an optical WDM transmission system including: creating, at the central network device, a broad-band optical signal, supplying the broadband optical signal, transmitting the broadband optical signal and the plurality of second optical channel signals to an optical demultiplexer device, transmitting an optical signal consisting of a dedicated second optical channel signal and a filtered broadband optical signal; receiving the optical signal and creating a corresponding electrical receive signal and extracting the electrical signal corresponding to the filtered broadband optical signal from the electrical receive signal and detecting whether the electrical signal contains information intended for the respective first channel transceiver.

A transponder includes a multiplexing section, optical transmitters, optical receivers, an extracting section, and a warning monitor section, wherein the extracting section includes a first signal extracting unit for extracting reception data, a second signal extracting unit for extracting reception data, and a reception signal switching section. When carrier signals are in a link-establishable state, the reception signal switching section supplies reception electric signals generated by the optical receivers to the first signal extracting unit and outputs the reception data. When a carrier signal is in a non-link-establishable state, the reception signal switching section supplies a reception electric signal generated by an optical receiver using a carrier signal in the link-establishable state to the second signal extracting unit and outputs the reception data extracted by the second signal extracting unit.

An optical Internet Protocol (IP) router serves a cell-site over an optical communication network. The optical IP router transmits a network attach request having an optical node name over a control optical wavelength. The optical communication node receives an assignment of a data optical wavelength, a cell-site mode, and an Internet Protocol (IP) address over the control optical wavelength based on the optical node name. The optical communication node operates in the cell-site mode and responsively exchanges cell-site data having the IP address over the data optical wavelength.

A communications network includes a central communication unit, an optical transport medium, and a plurality of remote radio base stations. The central communication unit generates, within a selected millimeter-wave frequency band, a plurality of adjacent two-tone optical frequency conjugate pairs. Each conjugate pair includes a first optical tone carrying a modulated data signal, and a second optical tone carrying a reference local oscillator signal. The optical transport medium transports the plurality of two-tone conjugate pairs to the plurality of radio base stations, and each base station receives at least one conjugate pair at an optical front end thereof. The optical front end separates the first optical tone from the second optical tone, and converts the first optical tone into a millimeter-wave radio frequency electrical signal. The base station further includes a radio antenna system for wirelessly transmitting the millimeter-wave radio frequency electrical signal to at least one wireless receiving device.

A radio frequency (RF) beam transmission component having optical inputs and electrical outputs may include a wavelength selective switch (WSS) that has a plurality of optical WSS outputs. Each optical WSS output may be configured to transmit one or more wavelengths of the incoming optical signals. The RF beam transmission component may include a plurality of photodetectors (PD), each photodetector having an optical PD input coupled to one or more of said plurality of optical WSS outputs and a corresponding electrical output of a plurality of PD electrical outputs. The RF beam transmission component may further include a lens that has a plurality of electrical inputs and each electrical input may be electrically coupled to at least one of the plurality of electrical PD outputs. The lens may further have a plurality of electrical lens output ports.

Embodiments of this application disclose an optical switch. The optical switch includes at least one first port, at least one second port, a first wavelength division multiplexing WDM apparatus, an optical splitter, an optical monitoring apparatus, and an optical switching apparatus. The first port is configured to transmit an input first optical signal to the first WDM apparatus, where the first optical signal is a multi-wavelength signal. The first WDM apparatus is configured to demultiplex the first optical signal. The optical splitter is configured to split a demultiplexed first optical signal to obtain a first sub-signal and a second sub-signal. The optical switching apparatus is configured to perform optical switching on the first sub-signal. The second port is configured to output a first sub-signal obtained after optical switching. The optical monitoring apparatus is configured to perform optical performance monitoring on the second sub-signal.