Nippon Telegraph and Telephone Corporation

Hidetoshi Onda

Masahiro Nakagawa

Kana Masumoto

Toshiya Matsuda

Masaru Katayama

Device cost and electric power consumption are reduced. Nodestoas optical add/drop multiplexers each include AWGsandconnected between light transmission paths as optical fibersandand transponderstoand configured to output optical signals from the light transmission paths to the transponderstothrough ports and transmit optical signals from the transponderstoto the light transmission paths through ports, and an optical couplerconfigured to connect ports of the AWGsandto the transponderstothrough coupling or bifurcation. The channel interval of ports of the AWGsandis multiple times larger than the channel interval of ports of the transpondersto, and transponder signals of a plurality of different wavelengths to and from one or a plurality of the transponderstocan pass through ports of the AWGsand

Optical branch insertion device and optical transmission system using optical branch insertion device

Device cost and electric power consumption are reduced. Nodestoas optical add/drop multiplexers each include cAWGsandthat include a plurality of first side ports and a plurality of second side ports connected between light transmission paths as optical fibersandand transponderstoand in which a first optical signal input-output channel interval of each port is a plurality of times larger than a second optical signal input-output channel interval of ports of the transponderstoand optical signals of a plurality of different wavelengths from one or a plurality of transponderstoor the light transmission paths can pass through a first channel. The cAWGsandcause the optical signals from the transponderstoto pass through the first side ports, and then cyclically outputs and transmits the optical signals through the plurality of second side ports in a predetermined order to the light transmission paths. The optical signals transmitted through the light transmission paths are caused to pass through the second side ports and then output from the plurality of first side ports in a predetermined order to the transpondersto

An optical demultiplexerincludes: a plurality of optical gate switchestoconfigured to transmit, when being turned on, and to block, when being turned off, a multiplexed optical signal obtained by multiplexing optical signals of a plurality of wavelengths by time-division multiplexing or wavelength-division multiplexing in addition to time-division multiplexing; and a cAWGincluding a plurality of input ports and a plurality of output ports and configured to input the multiplexed optical signal transmitted through the optical gate switchestofrom the plurality of input ports, demultiplex the input multiplexed optical signal for each wavelength, and cycle and output the demultiplexed optical signals from the plurality of output ports in a predetermined order.

Optical demultiplexer, optical separation device, optical transmission system, and optical transmission method

An object is to provide a dispersion compensating system with a large amount of dispersion compensation and reduced operation costs. Disclosed is a dispersion compensating system in which a core node and an access node are connected through a ring network, the access node includes a delay measurement unit configured to receive delay measurement signals from the core node to measure a delay between the core node and the access node, an average dispersion amount calculation unit configured to calculate an amount of dispersion compensation to be applied to an optical burst signal prior to transmission to the ring network, based on the delay thus measured, and a real-part inverse dispersion application unit configured to perform pre-equalization on a waveform of the optical burst signal prior to the transmission, based on the calculated amount of dispersion compensation.

Growing community of inventors

Tokyo, Japan

Hidetoshi Onda