Fujitsu Corporation

Masahiro Yuki

Kentaro Nakamura

George Ishikawa

Yuichi Akiyama

Takeshi Hoshida

Hiroki Ooi

Tomoo Takahara

Norifumi Shukunami

Takao Naito

Toshiki Tanaka

Yutaka Kai

Masato Nishihara

Naoki Kuwata

Takeshi Sakamoto

Shingo Hara

Yoshinori Nishizawa

Atsushi Kiyama

Takafumi Terahara

Hideyuki Miyata

Miki Onaka

Toru Katagiri

Akira Miura

Tomoaki Takeyama

Kosuke Komaki

Satoru Okano

Toshihiro Ohtani

Tsukasa Takahashi

Jens Rasmussen

Ryosuke Goto

Kazuo Takatsu

Tatsuya Tsuzuki

Yoshinobu Matsukawa

Kenichi Torii

Makoto Yamashita

Jens C Rasmussen

A transmission device, includes a first wavelength converter configured to convert a second wavelength-multiplexed signal in a first wavelength band to a second wavelength band different from the first wavelength band, and a multiplexer configured to transmit, after the conversion, a wavelength-multiplexed signal obtained through multiplexing of a first wavelength-multiplexed signal in the first wavelength band, a first supervisory control signal light ray that is a control signal for the first wavelength-multiplexed signal, the second wavelength-multiplexed signal in the second wavelength band, and a second supervisory control signal light ray that is a control signal for the second wavelength-multiplexed signal, wherein the first supervisory control signal light ray and the second supervisory control signal light ray each have a wavelength in a wavelength band different from the first wavelength band and the second wavelength band.

Transmission system, transmission device, and transmission method

An apparatus that adds and drops wavelength division multiplexed signal, the apparatus includes a memory and processor. The memory configured to store a first correspondence table indicating relationship with between an optical circuit type information and a first output level target value for a dropping circuit. The processor configured to determine an output level target value for the dropping circuit for each signal wavelength, based on the first correspondence table and optical circuit type information of each signal wavelength.

Apparatus and adding and dropping method

A transmitting device, includes inputting a multiplex light multiplexed a first wavelength-multiplexed signal light stream in a first wavelength band and a second wavelength-multiplexed signal light stream in a second wavelength band; inputting a multiplex light multiplexed a third wavelength-multiplexed signal light stream in a first wavelength band and a fourth wavelength-multiplexed signal light stream in a second wavelength band; converting the first wavelength-multiplexed signal light stream to the second wavelength band; converting the third wavelength-multiplexed signal light stream to the second wavelength band; generating a first output signal light multiplexed by signal light in a first wavelength band among the multi-wavelength light so that wavelengths do not overlap; generating a second output signal light multiplexed by signal light in a second wavelength band among the multi-wavelength light so that wavelengths do not overlap; converting the first output signal light to the first wavelength band; and outputting the multiplexed light.

Transmitting device and transmission system

An optical transfer method of an optical transfer system including a transmitter, a first wavelength converter configured to use first excitation light to perform wavelength-conversion of first signal light which is the transmission light into second signal light in a different wavelength band, a second wavelength converter configured to use second excitation light to perform wavelength-conversion of the second signal light into third signal light in a different wavelength band, and a receiver configured to receive the third signal light, the method includes acquiring a wavelength of the transmission light, a wavelength of the first excitation light, and a wavelength of the second excitation light; and deciding local emission light of the receiver based on a wavelength of reception light of the receiver obtained from the wavelength of the transmission light, the wavelength of the first excitation light, and the wavelength of the second excitation light.

Optical transfer system, control device, optical transfer method, and transfer device

An optical transmission device includes an optical amplifier that optically amplifies a wavelength multiplexing signal which is input, a wavelength selective switch that splits, inserts, or transmits an optical signal of any wavelength of the wavelength multiplexing signal, an optical channel power monitor that detects power of each channel of the wavelength multiplexing signal which is input and the wavelength multiplexing signal which is output, and a controller that calculates an amount of change in the optical signal of each channel in which a gain of each channel between an input and an output to and from the device is steady, and adjusts an amount of attenuation of the wavelength selective switch, based on the power of each channel of the wavelength multiplexing signal that is detected by the optical channel power monitor.

Optical transmission device and optical signal gain control method

An optical transmission device includes: a first optical amplifier, a WSS (wavelength selective switch), a second optical amplifier and a controller. The first optical amplifier amplifies a received WDM (wavelength division multiplexed) optical signal. The WSS controls optical powers of respective channels multiplexed in the WDM optical signal that is amplified by the first optical amplifier. The second optical amplifier amplifies the WDM optical signal output from the WSS. The controller controls a gain of the first optical amplifier based on initial setting information. The controller corrects the gain of the first optical amplifier such that an average optical power of a plurality of channels multiplexed in the WDM optical signal that is amplified by the first optical amplifier approaches a target level after a specified period of time has elapsed from when the gain of the first optical amplifier is controlled based on the initial setting information.

Device and method for transmitting wavelength division multiplexed optical signal

An optical transmission device that transmits an optical signal in a specified wavelength band includes: a receiver, a monitor light unit, a wavelength selective switch and a memory. The receiver receives the optical signal. The monitor light unit outputs monitor light of a wavelength allocated outside of the specified wavelength band. The wavelength selective switch outputs the optical signal via a first port and outputs the monitor light via a second port. The memory stores information that indicates an optical power loss of a route through which the monitor light is transmitted.

Optical transmission device and method for checking optical connection in optical transmission device

An optical transmission apparatus including: an attenuator that attenuates a power of a first optical signal generated in a first modulation method to a first target level and attenuates a power of a second optical signal generated in a second modulation method, a modulation level in the second modulation method being lower than the modulation level in the first modulation method, to a second target level, the second target level being lower than the first target level; and a transmitter that sends a WDM signal including the first optical signal and the second optical signal that have been attenuated by the attenuator.

Optical transmission apparatus and optical transmission system

An optical transmission device includes a receiver that receives first light, a transmitter that outputs second light, a memory, a processor coupled to the memory, configured to control a first optical level of the second light in such a way that a second optical level calculated based on an optical level of the received first light and an optical level of the second light that is output from the transmitter becomes a predetermined target value, a combiner that combines the received first light and the second light for which the first optical level is controlled by the processor, and an amplifier that amplifies the combined light.

Optical transmission device and optical transmission method

A communication system including: a transmission apparatus configured to modulate a first light by using a first signal to be transferred and a second signal having a frequency different from a frequency of the first signal so as to generate a first optical signal, modulate a second light by using a third signal to be transferred and a fourth signal having a frequency different from a frequency of the third signal so as to generate a second optical signal, polarization-multiplex the first optical signal and the second optical signal, and transmit a polarization-multiplexed optical signal in which the first optical signal and the second optical signal are polarization-multiplexed, each of the first light and the second light being polarized; and a measuring apparatus configured to measure powers of the second signal and the fourth signal which are included in the polarization-multiplexed optical signal transmitted from the transmission apparatus.

Communication system, measuring apparatus, transmitting apparatus, and measurement method

A phase shift unit provides a prescribed phase difference (&#x3c0;/2, for example) between a pair of optical signals transmitted via a pair of arms constituting a data modulation unit. A low-frequency signal fis superimposed on one of the optical signals. A signal of which phase is shifted by &#x3c0;/2 from the low-frequency signal fis superimposed on the other optical signal. A pair of the optical signals is coupled, and a part of which is converted into an electrical signal by a photodiode. 2fcomponent contained in the electrical signal is extracted. Bias voltage provided to the phase shift unit is controlled by feedback control so that the 2fcomponent becomes the minimum.

Optical transmitting apparatus, optical receiving apparatus, and optical communication system comprising them

According to an aspect of an embodiment, an apparatus includes an optical branching unit for branching an input signal light in four directions, a polarization component extraction unit extracting four polarization components having mutually different polarization parameters from lights branched in four directions by the optical branching unit, and a determination unit determining input/non-input of the signal light based on the four polarization components extracted by the polarization component extraction unit.

Signal light monitoring apparatus, optical amplification apparatus and optical reception apparatus, and signal light monitoring method

The present invention provides a control apparatus including: an output monitor which monitors polarization-multiplexed output light output from a polarization multiplexing light modulator which modulates light of two systems independent of each other, polarization-multiplexes light signals of the two systems subjected to the light modulation, and outputs the polarization-multiplexed light signals; and a control unit which controls a delay time difference at a stage where the light signals of the two systems forming the polarization multiplexing light modulator are polarization-multiplexed based on a monitor result of the output monitor. The control apparatus controls a delay time difference between polarization channels easily or surely.

Control apparatus, polarization multiplexing light modulator, light transmitting apparatus, and method of controlling polarization multiplexing light modulator

The disclosed device and method include varying phases of two data signals at a first predetermined frequency, performing multi-level phase modulation of a light based on the two data signals whose phases are varied at the first predetermined frequency, extracting a component having the first predetermined frequency from an optical signal subjected to the phase modulation, and controlling the phases of the two data signals based on the component extracted from the optical signal.

Growing community of inventors

Kawasaki, Japan

Masahiro Yuki