Fujitsu Corporation

Fujitsu Telecom Networks Limited

Yuichiro Sakane

Koji Matsunaga

Koji Bato

Tatsuya Toyozumi

Wataru Kawasaki

Akira Yamamoto

Tomoyuki Sakata

Tatsuhiko Saito

Yasuo Tanaka

Hiromu Yoshii

Tatsuro Kishida

Yasushi Sugaya

Masahiro Oohashi

Satsuki Norimatsu

Kouichi Maeda

Akihiro Horiuchi

Ryuta Hoshi

Tsutomu Tsurumi

Haruka Miyazaki

Tomonori Yamada

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 inter-integrated circuit (I2C) communication device, includes an I2C command transmission unit that transmits an expanded command to an optical module with which the I2C command transmission unit communicates together with software data, the expanded command including a command for transmitting the software data to the optical module and a command for collecting alarm monitor information from the optical module for monitoring the occurrence of an abnormality in the optical module, and an I2C command processing unit that, when the expanded command transmitted from the I2C command transmission unit is received, stores the software data transmitted together with the expanded command in a storage unit of the optical module, reads out the alarm monitor information stored in the storage unit, and transmits the read alarm monitor information to the I2C command transmission unit.

I2C communication device and I2C communication method

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 transmitter and receiver has stored in advance therein FEC techniques and applicable conditions for applying the FEC techniques to a counterpart optical transmitter and receiver. The optical transmitter and receiver measures a state of receiving data transmitted from the counterpart optical transmitter and receiver, determines an applicable condition satisfying the measured data reception state from among the stored applicable conditions, and selects a FEC technique stored in association with the applicable condition determined as satisfying. The optical transmitter and receiver then notifies the counterpart optical transmitter and receiver of the selected FEC technique.

Optical transmitter and receiver and optical transmission and reception system

An optical pickup which has a failure prediction apparatus for predicting a failure of a laser diode has an input inputting a value of a current that flows through the laser diode and is measured at predetermined time intervals, a storage storing the current values inputted by said input, a detector detecting a current value that is a current value at any one of the measurement times of day stored in said storage and that has a change greater than or equal to a predetermined value relative to the current value at the preceding measurement time of day, and a generator generating a prediction curve that indicates a relationship between said elapsed time and the current value applicable at and after the measurement time of day of the current value detected by said detector.

Failure prediction apparatus and failure prediction method

An aspect of the embodiments utilizes an optical transmission apparatus which includes a rough adjustment execution portion that monitors a bit error rate of an optical signal for set values of a dispersion compensator where the set values have been set less closely to each other within a dispersion compensation control range than when a wavelength dispersion value set in the dispersion compensator is determined, and carries out a rough adjustment to determine a comparison threshold value used to set the wavelength dispersion value based on the monitored bit error rate, and a fine adjustment execution portion that monitors the bit error rate for the dispersion compensator the set values have been set more closely to each other, and carries out an adjustment to determine a wavelength dispersion value corresponding to the midpoint between the two acquired bit error rates as the wavelength dispersion value of the dispersion compensator.

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Fukuoka, Japan

Yuichiro Sakane