A network or system in which a hub or primary node may communicate with a plurality of leaf or secondary nodes. The hub node may operate or have a capacity greater than that of the leaf nodes. Accordingly, relatively inexpensive leaf nodes may be deployed to receive data carrying optical signals from, and supply data carrying optical signals to, the hub node. One or more connections may couple each leaf node to the hub node, whereby each connection may include one or more spans or segments of optical fibers, optical amplifiers, optical splitters/combiners, and optical add/drop multiplexer, for example. Optical subcarriers may be transmitted over such connections, each carrying a data stream. The subcarriers may be generated by a combination of a laser and a modulator, such that multiple lasers and modulators are not required, and costs may be reduced. As the bandwidth or capacity requirements of the leaf nodes change, the number of subcarriers, and thus the amount of data provided to each node, may be changed accordingly. Each subcarrier within a dedicated group of subcarriers may carry OAM or control channel information to a corresponding leaf node, and such information may be used by the leaf node to configure the leaf node to have a desired bandwidth or capacity.

Disclosed are an apparatus and testing methods for performing testing operations over multiple types of links and through multiple potential points of failure to segment sources of problems, which may relate to reported or actual instances of service disruption in a network communication environment. The apparatus may perform service layer testing directly via an optical link, in addition to via Ethernet service layer testing. The apparatus may further conduct tests on other layers as well, including the physical layer, the network layer, and the link layer. To facilitate efficient testing, the apparatus may integrate programmable workflow profiles that specify tests to be conducted, and may interface with a cloud platform for sharing results of the tests, providing end-to-end testing of various components and types of links (whether optical or electrical, including wired and wireless links). Results of the tests may provide guidance to resolve detected problems.

Aspects of the present disclosure describe distributed fiber optic sensing (DFOS) systems, methods, and structures that advantageously overcome problems encountered when operating DFOS systems over operational telecommunications facilities namely, cross-phase modulation, and uneven amplitude profiles through the use of a novel constant amplitude coded DFOS employing suppressed out-of-band signaling.

An optical transmission apparatus includes a multiplexing unit multiplexing signal light of a main signal, and dummy lights of odd channel and an even channel emitted using first and second dummy light sources, respectively, a detection unit detecting abnormality of the first and second dummy light sources, and a control unit performing addition control. The addition control includes control in such a way that dummy light of an even channel emitted using the first dummy light source is additionally multiplexed with the signal light, when no abnormality is found in the first dummy light source and an abnormality of the second dummy light source is detected, and that dummy light of an odd channel emitted using the second dummy light source is additionally multiplexed with the signal light, when no abnormality is found in the second dummy light source and an abnormality of the first dummy light source is detected.

An optical transmission apparatus includes a multiplexing unit multiplexing signal light of a main signal, and dummy lights of odd channel and an even channel emitted using first and second dummy light sources, respectively, a detection unit detecting abnormality of the first and second dummy light sources, and a control unit performing addition control. The addition control includes control in such a way that dummy light of an even channel emitted using the first dummy light source is additionally multiplexed with the signal light, when no abnormality is found in the first dummy light source and an abnormality of the second dummy light source is detected, and that dummy light of an odd channel emitted using the second dummy light source is additionally multiplexed with the signal light, when no abnormality is found in the second dummy light source and an abnormality of the first dummy light source is detected.

A method and apparatus for transmitting and receiving signals in a wireless communication system, according to an embodiment of the present invention, may comprise a feature of applying a phase pattern to a wavefront of an optical signal and a feature of transmitting the optical signal. The phase pattern may be determined on the basis of an optical phase shift characteristic of a phase mask, and the phase mask may be determined on the basis of a quantization order and a phase order.

This application provides a signal processing method and apparatus, and a coherent receiver. The signal processing method includes: obtaining P real-number signals; performing at least number theoretic transform NTT processing on the P real-number signals to obtain P transform-domain first real-number signals; performing at least clock recovery on the P transform-domain first real-number signals to obtain P transform-domain second real-number signals; performing at least polarization compensation and inverse number theoretic transform INTT processing on the P transform-domain second real-number signals to obtain m time-domain complex-number signals X and m time-domain complex-number signals Y; and performing phase recovery and decoding on the m time-domain complex-number signals X and the m time-domain complex-number signals Y to obtain bit signals.

A quantum telecommunications network includes nodes, typically on the ground; a conventional telecommunications network connecting the nodes to one another; and at least one satellite or airborne carrier able to generate and transmit multiplets of entangled photons to the nodes. The nodes are configured to collect photons from the satellite, take joint quantum measurements and exchange conventional information with other nodes via the conventional telecommunications network. Node and satellite payload for such a quantum telecommunications network. Method for quantum telecommunications by way of such a network.

An integrated receiver chip comprising: a first end and a second end; at least one optical input port disposed at the first end; a polarization manipulation device optically connected to one of the at least one optical input port, the polarization manipulation device being adapted to split an optical signal into a first and a second optical signals; a first and a second dispersion compensators each optically connected to the polarization manipulation device, the first and the second dispersion compensators each being adapted to selectively induce a dispersion on an optical signal propagating through the dispersion compensator; and a first and a second photodetectors optically connected to the first and the second dispersion compensators, respectively.

Systems and methods for compensating for spectrum power offsets with respect to a target profile are provided. A method, according to one implementation, includes determining whether an upstream controller is currently performing an upstream action, or intends to perform the upstream action soon thereafter, with respect to an upstream power compensation unit. The method also includes determining whether there is a need to perform a local action with respect to the local power compensation unit. Furthermore, the method includes the step of performing the local action with respect to the local power compensation unit in response to determining that (a) the upstream controller is not currently performing the upstream action (or does not intend to perform the upstream action soon thereafter) and (b) there is a need to perform the local action.