An optical add/drop device (100) comprising: a common port (102); an add port (106); a first wavelength selective optical filter (110) configured to: receive an optical signal at an add wavelength from the add port and transmit said optical signal at the add wavelength towards the common port; and receive optical signals from the common port and reflect optical signals not at the add wavelength; a second wavelength selective optical filter (114) configured to receive said optical signals from the common port reflected by the first wavelength selective optical filter and transmit an optical signal at a drop wavelength, different to the add wavelength; a drop port (116); and an optical waveguide (118) configured receive said optical signal at the drop wavelength transmitted by the second wavelength selective optical filter and route said optical signal to the drop port.

An optical fiber includes: a first core portion capable of transmitting first light; a second core portion formed on an outer periphery of the first core portion in a structure different from that of the first core portion and capable of transmitting second light different from the first light. The second core portion is formed around the outer periphery of the first core portion, and a center of the second core portion is positioned in a region of the first core portion.

A single-fiber bidirectional optical ring system includes: a central station; slave stations; and a network which connects the central station and the slave stations in a ring shape by optical fibers. The central station includes: a first single-fiber bidirectional optical transceiver connected in a clockwise direction of the network, which outputs a downstream optical signal of a second wavelength and receives an upstream optical signal of a first wavelength; a second single-fiber bidirectional optical transceiver connected in a counterclockwise direction of the network, which outputs a downstream optical signal of the second wavelength and receives an upstream optical signal of the first wavelength; and a first time synchronization control circuit that adjusts timings at which the downstream optical signals of the second wavelength are outputted, and causes the first and second single-fiber bidirectional optical transceivers to output the downstream optical signals of the second wavelength in different time slots.

A wall plate is provided having a built-in modem on the backside of the wall plate that performs O/E, E/O and protocol conversions. The backside of the wall plate has an optical port for connecting an end of an optical fiber cable to the wall plate. A printed circuit board (PCB) disposed on the backside of the wall plate has electrical circuitry mounted thereon that performs protocol conversion and communicates with an optical transceiver module also mounted on the PCB. The optical transceiver module receives optical signals transmitted to the customer premises and transmits optical signals from the customer premises and performs O/E and E/O conversion. A front face of the wall plate has at least one socket therein for connection with an electrical connector disposed on an end of an electrical cable. The wall plate does not require a separate power supply.

A downhole optical communications system provided at a downhole location in use, the downhole communications system being for communicating between the downhole location and an uphole location, such as a surface location. The downhole optical communications system comprises a downhole optical transmitter configured to emit an optical signal for transmission over an optical transmission channel between the uphole location and the downhole optical transmitter; wherein the downhole optical transmitter is configured so as to produce a response to an optical signal received from the optical transmission channel and the downhole optical communications system is configured to determine data represented by the received optical signal from the response produced by the downhole optical transmitter.

An EMC test bench, includes an item of equipment under test to be loaded on board an aircraft, the item of equipment being subjected to EMC tests and delivering ARINC electrical interfaces as inputs and as output; an electrical interfaces device representative of an item of anti-lightning equipment and including an ARINC signals acquisition and/or generation card connected to the ARINC inputs and outputs of the item of equipment under test; a command and control rack for analyzing control signals originating from the electrical interfaces device including the ARINC signals acquisition and/or generation card, and a signals conversion system for protecting the command and control rack connected between the command and control rack and the electrical interfaces device.

This disclosure describes a wavelength division multiplexing passive optical network system (100) comprising an optical line terminal (180) for controlling transmission of data that are carried by optical signals across the optical network system along an upstream or downstream path; a signal modulating loop circuit including a circulator (110) connected to the optical line terminal (180) for determining the transmission paths of the optical signals; a splitter (120) connected to the circulator (110) for splitting the optical signals into a first portion of optical signals and a second portion of optical signals according to a predetermined ratio; an amplifier (160) connected to the splitter (120) for amplifying the second portion of optical signals; and a modulator (170) connected in between the amplifier (160) and the splitter (120) for modulating the amplified second portion of optical signals to be transmitted to the circulator (110); a converter (140) connected to the splitter (130) for converting the first portion of optical signals into electrical signals; and one or more optical network units (150) connected in between the converter (140) and modulator (170) for receiving the electrical signals from the converter (140), and transmitting electrical signals to the modulator (170) for converting the electrical signals into optical signals to be transmitted together with the amplified second portion of optical signals to the optical line terminal (180); wherein the circulator (110) directs the optical signals received from the modulator (170) to the splitter (120) for being transmitted back into the signal modulating loop circuit and/or towards the optical network units along the downstream path, or towards the optical line terminal along the upstream path.

An electromagnetic signal transport and distribution system and method provides for aggregating signals from multiple transport media and for distributing the signals to multiple end points in one or multiple formats to suit end user devices.

The present technology relates to a transmission apparatus, a transmission method, and a filter circuit that make it possible to transmit a signal with high quality, the signal including a plurality of signals having different speeds. The transmission apparatus includes a detection unit that detects each of a plurality of signals having different speeds from an input signal. Further, the transmission apparatus includes an output control unit that controls output of an output signal including the plurality of signals, on the basis of detection results of the plurality of signals by the detection unit. The present technology can be applied to, for example, a transmission apparatus that transmits a serial signal conforming to the USB 3.0 standards or a transmission apparatus that converts the serial signal described above into a millimeter-wave signal or an optical signal and sends and receives the signal.

The invention relates to an optical WDM transmission network including at least one optical line terminal, a remote node and a plurality of optical network units. The at least one optical line terminal is connected to the optical remote node via an optical WDM path. Each optical network unit is connected to the optical remote node via an optical distribution path.