To provide a submarine branching unit that enables interconnection between the trunks of two different systems and allows them to communicate with each other. A submarine branching unit comprising: two first system-side trunk line pairs L1 and L2 that are arranged in parallel between a first trunk and a second trunk; two second system- side trunk line pairs L3 and L4 that are arranged in parallel between a third trunk and a fourth trunk; and an optical switch group configured to switch the connection state between the first system-side trunk line pairs and the second system-side trunk line pairs in accordance with control from a control unit 20.

The disclosure provides a microwave photon frequency synthesis system and method. In the disclosure, based on various combinations of path switching options of optical routing modules and electrical routing modules, the microwave photon frequency synthesis system is provided with a direct photoelectric conversion mode, an electrical frequency synthesis mode and an optical amplitude and phase control mode. The first optical signal frequency selection based on the optical frequency comb module and the frequency multiplication/division selection of the optical frequency multiplication/division module can be freely combined to realize frequency sources of various frequencies. Based on the optical frequency comb module to generate the first optical signal, and then combined with an electrical filtering module, phase noise can be reduced. The optical amplitude and phase may be controlled by the optical amplitude and phase control module.

An apparatus for optical demultiplexing comprising an optical splitter, at least two semiconductor optical elements (SOE's), and an optical gating line arrangement optically coupled to each of the at least two SOE's for altering optical transmission properties of the corresponding SOE.

An optical transceiver includes an optical transmission unit and an optical reception unit and constitutes a network. The optical transmission unit transmits data at a symbol rate common in the network. The optical transceiver includes: an N-input-1-output optical switch that switches an optical signal received by the optical reception unit; a 1-input-N-output optical switch provided upstream of the optical signal with respect to the optical switch; and N delay lines of different lengths connected between the optical switch and the optical switch, and the optical signal input to the optical switch is input to the optical switch through one of the optical waveguides and received by the optical reception unit.

This application provides an optical communication system and a communication method. The optical communication system includes: a first WSS, configured to transmit an optical signal with a first wavelength to a second WSS through a first link; the second WSS, configured to transmit the first optical signal with the first wavelength to a second node; a third WSS, configured to transmit an optical signal with a second wavelength to a fourth WSS through a second link; the fourth WSS, configured to transmit the optical signal with the second wavelength to the second node, where the third WSS is configured to transmit an optical signal with a third wavelength to the second WSS through a third link, and the second WSS is configured to transmit the optical signal with the third wavelength to the second node.

Systems and methods for switching are disclosed. In an example, a switching system includes a photonic integrated circuit (PIC) having optical ports, an electric integrated circuit (EIC) stacked on the PIC and having switching circuitry, and photonic transceivers optically coupled to the optical ports of the PIC and electrically coupled to the switching circuitry of the EIC, and the switching circuitry is configured to transfer digital signals, which are generated from optical signals received at a first photonic transceiver of the photonic transceivers, to a second photonic transceiver of the photonic transceivers based on information in the digital signals, wherein the first photonic transceiver is optically coupled to a first optical port of the PIC and the second photonic transceiver is optically coupled to a second optical port of the PIC.

An object of the present invention is to provide an optical switch element, an optical switch device, an optical communication system, and an optical computer capable of operating even in a temperature range higher than the Nel temperature. An optical switch element (10) according to the present invention includes a substance including a plurality of transition metal elements having electrons in d-orbitals, and a plurality of anions arranged around each of the plurality of transition metal elements, in which the plurality of transition metal elements are arranged in a lattice form, t.sub.2g-orbitals into which the d-orbitals of each of the plurality of transition metal elements are split are connected annularly, and in a state in which the substance does not have a long-range magnetic order, the polarization of signal light (L1) is rotated when control light (C1) is applied.