Fujitsu Corporation

Takashi Toyomaki

Motoyoshi Sekiya

Noriaki Mizuguchi

Toru Katagiri

Kazuyuki Tajima

Tomohiro Hashiguchi

Yoichi Oikawa

Takuya Miyashita

Kenichi Kaburagi

Yoshikazu Terayama

Takeshi Hoshida

Yutaka Takita

Jens Rasmussen

Taizo Maeda

Akihiko Isomura

Eiji Ishikawa

Tomoyuki Ohtsuka

In an optical communication device, a light source is capable of varying the wavelength of light to be output. An optical multiplexer multiplexes light output from the light source with signal light received from a transmission path. To an optical medium, light output from the optical multiplexer is input. A monitor monitors light having a predetermined wavelength output from the optical medium. A wavelength number measuring unit measures the number of wavelengths of signal light transmitted through the transmission path based on the result of monitoring by the monitor.

Optical communication device, wavelength number measurement device, optical repeater, and wavelength number measurement method

An optical transmission apparatus includes an optical transmitter that outputs a signal light corresponding to a wavelength of a WDM light, a multiplexer that multiplexes lights input to the plurality of input ports, and that outputs a light generated through the multiplexing from the one or more output port, an optical amplifier that amplifies the light output from the multiplexer; and an amplified spontaneous emission (ASE) transmitter that inputs branching off part of the light output from the optical amplifier by a splitter and multiplexes, with the signal light, ASE in a wavelength band corresponding to an unused wavelength adjacent to the signal light included in the branched-off light.

Optical transmission apparatus and optical transmission system

An optical transmission device includes a signal generator configured to generate a first signal corresponding to an amount of residual chromatic dispersion that occurs in a light signal transmitted from the optical transmission device to a downstream device, and a superimposer configured to superimpose the first signal on the light signal transmitted from the optical transmission device and transmit the light signal superimposed by the first signal to the downstream device.

Optical transmission device and optical switch device

An optical transmission system includes a plurality of optical nodes that transmits wavelength multiplexing light including a plurality of signal light components having different wavelengths, wherein each of the optical nodes includes superimposed signal light generation circuit which superimposes a low frequency signal having a common frequency on a corresponding signal light component included in the wavelength multiplexing light; low frequency signal extraction circuit which extracts a low frequency signal having a frequency of a given range from a corresponding signal light component; and pass-through node number measurement circuit which measures, for each of the signal light components, a pass-through node number based on the frequency of the low frequency signal extracted by the low frequency signal extraction circuit, the pass-through node number being the number of optical nodes through which the signal light component has passed before being transmitted to a specific optical node.

Optical transmission system and optical transmission method

An optical apparatus comprising, converting units converting electrical signals into signal lights with different wavelength, polarization control units controlling polarizing states of the signal lights into polarization controlled lights respectively, an optical multiplexer multiplexing the polarization controlled lights into a multiplexed light, an optical branching unit branching the multiplexed light and outputting a branched light, a polarizing unit extracting only signal lights of the specified polarizing state from the branched light into an extracted light, and a control unit detecting intensity of the extracted light. Pilot signals are applied to modulate the electrical signals or the polarization controls. The polarization control units controls the polarizing states of the signal lights based on the pilot signal frequencies of the detection result by the control unit.

Optical apparatus using polarized orthogonal control

A residual chromatic dispersion target value at a terminal node is set for each wavelength path, and also, candidates of a dispersion compensation amount settable in each chromatic dispersion compensation module on an optical network are set, and further, computation processing is executed for selecting the dispersion compensation amount in each chromatic dispersion compensation module from the candidates so that the sum of errors between the residual chromatic dispersion amounts and the set residual chromatic dispersion target values at the terminal nodes for all of wavelength paths becomes minimum. As a result, for each wavelength path on the optical network, the dispersion compensation amount in each chromatic dispersion compensation module can be designed in optimum so as to satisfy the desired optical signal quality at the terminal node, while considering the residual chromatic dispersion during the transmission.

Chromatic dispersion compensation designing method in optical network and a system thereof

A network design apparatus designs arrangement of various types of optical transmission devices in stations within a linear section in a network. An acquisition unit acquires information concerning the type of optical transmission device to be provided in the stations, and information concerning cost and transmission degradation for the optical transmission devices. The designing unit designs, based on the information acquired by the acquisition unit, an arrangement for which transmission degradation between stations respectively including an optical transmission device applicable as an optical regenerative repeater, is less than or equal to a threshold, and also has the least cost. An output unit outputs information concerning the arrangement designed by the design unit.

Network design and determination of the arrangement of optical transmission devices in respective network stations

An optical apparatus comprising: a branching unit branching an input light modulated by DQSPK format and thereby outputting a first branched light and a second branched light; a first branch and a second branch inputting the first branched light and the second branched light, respectively, the first branch and the second branch having an interferometer, a photo detector, and discriminator and demodulating I-signal and Q-signal, respectively; and an abnormality detection unit detecting an abnormality of the input light based on a synchronized detection of a first demodulated signal output from the photo detector in the first branch and a first recovered signal output from the discriminator in the first branch, and a synchronized detection of a second demodulated signal output from the photo detector in the second branch and a second recovered signal output from the discriminator in the second branch.

Detecting abnormality in an optical receiver

In a CWDM optical transmission system of the present invention, in place of an optical signal of at least one wave among a plurality of optical signals corresponding to a CWDM system, a DWDM light output from an additional light transmission unit of a DWDM system is given to a multiplexer via a variable optical attenuator, and multiplexed with the optical signals corresponding to CWDM, to be sent out to a transmission path. At this time, the total power of the DWDM light sent out to the transmission path, is attenuated by the variable optical attenuator, so as to be approximately equal to the power per one wavelength of the CWDM light. On an optical reception terminal, the light propagated through the transmission path is demultiplexed by a demultiplexer, and the DWDM light corresponding to the additional wavelengths is amplified by an optical amplifier and thereafter, received by an additional light reception unit. As a result, the addition of optical signals in the CWDM system can be realized at low-cost, while avoiding the reduction in transmission quality.

Coarse wavelength division multiplexing optical transmission system, and coarse wavelength division multiplexing optical transmission method

A calculation processing unit controls temperature of a Peltier device based on a slope of a waveform obtained by subtracting a waveform of a B-arm monitoring signal from a waveform of an A-arm monitoring signal and a value obtained by subtracting a value B of the B-arm monitoring signal from a value A of the A-arm monitoring signal. Similarly, the calculation processing unit controls a phase of the A-arm and a phase of the B-arm. An A-arm side micro-controller controls temperature of an A-arm side heaterbased on the value of the A-arm monitoring signal, and controls the phase of the A-arm. A B-arm side micro-controller controls temperature of a B-arm side heater based on the value B of the B-arm monitoring signal, and controls the phase of the B-arm.

Phase control apparatus and optical DQPSK receiver

A communication system that improves operation and maintenance and controls communication efficiently. A supervisory signal sending control section controls the sending of a supervisory signal for having supervisory control of optical communication and a drive supervisory signal for controlling the driving of an optical fiber amplifier for performing optical amplification by using a non-linear optical phenomenon in an optical fiber. A sending stop section receives a stop signal and stops the sending of the drive supervisory signal. A drive control section receives the drive supervisory signal and controls the driving of the optical fiber amplifier. A stop signal sending section sends the stop signal to a sending unit after the optical fiber amplifier being driven.

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Kawasaki, Japan

Takashi Toyomaki