Fujitsu Corporation

Fujitsu Telecom Networks Limited

Tatsuya Toyozumi

Koji Matsunaga

Wataru Kawasaki

Yuichiro Sakane

Koji Bato

Yasuo Tanaka

Tatsuhiko Saito

Tomoyuki Sakata

Tatsuro Kishida

Yuji Takahashi

Tadashige Iwao

Shota Mori

Masahiro Shioda

Atsuki Taniguchi

Syunsuke Koga

Junichi Sawada

Yumiko Ogata

Shinji Takao

Hidetoshi Amari

Masato Miyake

Yuri Noguchi

Hironobu Fukuura

Tomonori Yamada

Nobuhiko Usui

Masayuki Maehira

An optical transmitter includes a dummy optical source, a polarized wave beam coupler, and an auto gain control (AGC)-system amplifier. The dummy optical source outputs, out of an optical signal in which an optical path signal and an optical packet signal are mixed, a dummy signal having a wavelength identical to that of the optical packet signal. The polarized wave beam coupler multiplexes the dummy signal with the optical signal so that the dummy signal is orthogonal to the optical signal so as to output an output signal. The AGC-system amplifier inputs the output signal, and amplifies the output signal with a predetermined amplification factor corresponding to a power difference between input power and output power of an optical amplifier.

Optical transmitter and optical transmission method

An optical transmitter includes an amplifying unit, a monitor, an identifying unit, and a controlling unit. The amplifying unit amplifies an optical signal in which an optical packet signal is mixed in optical path signals. The monitor monitors power of the optical signal on an input stage and an output stage of the optical amplifying unit, respectively. The identifying unit identifies an optical packet signal section on the input stage side based on the monitoring result on the input stage side, and identifies an optical packet signal section on the output stage side based on the monitoring result on the output stage side. The controlling unit compares the power of the identified section on the input stage side with the power of the identified section on the output stage side, and controls an amplification factor of the amplifying unit based on a power difference resulting from the comparison.

The optical transmission device includes an N&#xd7;N optical switch, an optical packet receiver and an optical packet generation unit. The N&#xd7;N optical switch transmits data in which a plurality of optical signals each having a different wavelength is multiplexed. The optical packet receiver detects change in the number of wavelengths of optical signals constituting the data. The optical packet generation unit generates, when the change is detected by the optical packet receiver, data to be transmitted by the N&#xd7;N optical switch, using optical signals for the number of wavelengths after the change.

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

An optical communication apparatus includes a variable resistor unit, a measurement unit, and a control unit. The variable resistor unit is arranged at a pre-stage of an electrical/optical conversion unit, which converts an electrical signal obtained by converting an input packet to an optical signal having a waveform corresponding to a potential difference between a positive phase component and a negative phase component of the electrical signal by using the potential difference. The variable resistor unit provides a resistor that varies a midpoint of potential of the positive phase component or the negative phase component. The measurement unit measures a ratio of a presence period, which is a period where the input packet is present, to a sum of the presence period and a non-presence period. The control unit controls a value of the resistor provided to the positive phase component or the negative phase component based on the ratio.

Optical communication apparatus and control method thereof

An optical transmission device that receives a wavelength division multiplexed optical signal obtained by dividing an optical packet signal and performing wavelength multiplexing and that transmits via an optical switch the received wavelength division multiplexed optical signal includes an optical power level measurement unit configured to measure respective optical power levels of respective optical signals of wavelengths included in the wavelength division multiplexed optical signal, and a routing information determinator configured to determine routing information of the wavelength division multiplexed optical signal on the basis of the measured optical power levels.

Optical transmission device and method

An optical packet switching device causes branching of an optical packet that is input to an optical switch and detects a synchronization pattern having a predetermined number of bits from the branched optical packet. Then, the optical packet switching device calculates a synchronization point indicating a location of the synchronization pattern with respect to a detection timing and controls, in accordance with the calculated synchronization point, a delay amount of a delay element that delays an optical packet ON signal that is output to the optical switch.

Optical communication device and signal adjusting method

A first node apparatus includes: ports; a storage device; and receiving, updating, and transmitting circuits. The storage device stores: information associating, with first identification information identifying a first frame, information distinguishing a first port having been used as a destination port when the first node apparatus has transmitted the first frame; and information associating, with each node apparatus, state information indicating whether frame transmission from each port is feasible. The receiving circuit receives, from a second node apparatus, a second frame including second identification information. When the second identification information is identical with the first, the updating circuit updates the state information associated with a node apparatus being a destination of the second frame to make the state information indicate frame transmission from the first port is not feasible. The transmitting circuit selects a second port from which transmission of the second frame is feasible, and transmits the second frame.

Node apparatus and communication method

A transmission device capable of configuring a communication network over which MC packets are forwarded in a way that does not use bands with futility is disclosed. The transmission device is so configured to transmit, when receiving a multicast packet from a host, to the other transmission device the multicast packet that is to be discarded by the transmission device having no necessity of forwarding the received multicast packet to the next transmission device.

Transmission device

In a light transmission equipment which can generate a desired concatenation signal from a maximum concatenation signal standardized in a synchronous transmission mode, a master and a slave circuit for clock change are provided respectively inputting at least two data at a maximum transmission rate based on a concatenation standard of a synchronous transmission mode obtained by dividing a desired transmission rate not prescribed in the concatenation standard to perform a concatenation control to the slave circuit by control information from the master circuit side.

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Onojo, Japan

Tatsuya Toyozumi