Yokogawa Electric Corporation

Chie Sato

Akira Miura

Tsuyoshi Yakihara

Shinji Kobayashi

Shinji Iio

Sadaharu Oka

Morio Wada

Katsuya Ikezawa

Masayuki Suehiro

Yoshiyuki Asano

Daisuke Hayashi

Akira Toyama

Hirotoshi Kodaka

Shin-ichi Nakajima

Hiroshi Sugawara

Yasukazu Akasaka

Mamoru Hihara

Tadashige Fujita

Akira Nagashima

Shinichi Nakajima

Isao Uchida

Machio Dobashi

Yusuke Kishine

Hiroshi Shimizu

Hiroyuki Matsuura

Shoujirou Araki

Minoru Akutsu

Tetsuya Ohtani

Hironori Okita

Toshimichi Suzuki

Kousuke Doi

Masamichi Ohashi

Shun-ichi Miyazaki

Naoaki Machida

Shigeo Uneme

Kanji Tatsumi

Ikurou Aoki

An optical packet network system of a ring type, capable of preventing degradation of an optical signal, can be implemented by providing a mechanism relatively simple in structure, capable of erasing light noise if the optical packet signal does not exists. In the optical packet network system made up by interconnecting respective nodes adjacent to each other, and connecting a sending source of an optical packet signal to a ring, a light noise removal function block is provided between the respective nodes adjacent to each other.

Optical packet network system

An optical communication apparatus includes an erbium-doped optical fiber amplifier for amplifying a modulated optical signal, wherein a light which is not modulated is inputted to the erbium-doped optical fiber amplifier together with the optical signal.

Optical communication apparatus

The present invention makes improvements in a mobile communication system that performs a communication via a communication network provided in a mobile body to execute a data transfer. The present system comprises a plurality of nodes, a path control device which receives data from the nodes respectively, selects a path for the data transfer on the communication network, and outputs the data, first optical fibers which connect each of the nodes and the path control device and transfer the data, and second optical fibers provided in parallel with the first optical fibers. In the present system, the path control device communicates with the node via the second optical fiber when a failure occurs in the first optical fiber.

Mobile communication system

A clock reproducing apparatus includes a clock reproducing circuit having: a gated oscillator having an oscillating circuit of two routes; and a frequency control circuit for comparing a phase of an output of the gated oscillator with a phase of a reference clock, and supplying a phase control signal to the gated oscillator based on the comparison result so as to set a delay time, input data is input to a reset input terminal of the gated oscillator, and different route of the two routes of the oscillating circuit operates depending on a case where the input data is 'H' and a case where the input data is 'L'.

Clock reproducing apparatus

In a forward error correction method and a forward error correction addition apparatus, error correction is performed on the basis of data, to which forward error correction code is added, transmitted through a network to output decoded data. The data transmitted through the network includes information bits represented by an information bit matrix with n rows and m columns (n, m are natural numbers), and redundancy bits represented by an odd number of redundancy information bit rows and an odd number of redundancy information bit columns based on the information bit matrix, which are provided in the row direction and in the column direction of the information bit matrix respectively. The redundancy bits are the forward error correction code.

Forward error correction method and communication method, and forward error correction code addition apparatus and communication apparatus

An optical waveform shaping device includes a first waveguide portion, formed on a substrate, for transmitting the optical signal and simultaneously absorbing a portion of the optical signal, which has a signal level equal to or smaller than a predetermined value, so as to shape the optical signal; and a second waveguide portion, formed on the substrate, for transmitting the optical signal, which was transmitted through the first waveguide portion, and simultaneously amplifying the optical signal. The first waveguide portion may be formed using a saturable absorber. A first electrode for supplying electric current to the first waveguide portion so that the first waveguide portion is provided with a function of absorbing the optical signal; and a second electrode for supplying electric current to the second waveguide portion so that the second waveguide portion is provided with a function of amplifying the optical signal may also be provided.

Optical waveform shaping device including portions for respectively absorbing and amplifying transmitted optical signal

Disclosed is a repeater including: a recognizing unit to recognize a destination address of an optical packet from the optical packet which includes the destination address assigned in unit of bit and a bit indicating whether or not a plurality of destination addresses are assigned; an optical splitting unit to split the optical packet into a plurality of optical packets; and selecting units to select transmission channels for the split optical packets on the basis of recognition results by the recognizing units, respectively.

Repeater and optical communication system

A variable light signal delay apparatus includes a first delay optical fiber, a second delay optical fiber having a length different from the first delay optical fiber, and an optical switch having two input ports, two output ports, and paths, through which a light signal propagates, provided between the first delay optical fiber and the second delay optical fiber, in which a light signal input from at least one of the input ports propagated through either the first delay optical fiber or the second delay optical fiber or through neither the first delay optical fiber nor the second delay optical fiber to be output from a desired first output port.

Variable light signal delay apparatus, and variable light signal delay system using the same

An object of this invention is to realize a pulse pattern generating apparatus that outputs a test signal of high waveform quality even when the shape of an eye pattern is changed. This invention is an improvement of a pulse pattern generating apparatus that generates a test signal of a predetermined pattern by using plural digital-analog converters and outputs the test signal to a test subject. The apparatus includes: a parameter setting unit for setting values of plural parameters that determine the shape of an eye pattern of the test signal; a storage unit for storing output values to the digital-analog converters corresponding to the values of the parameters; an arithmetic operation unit for calculating output values to the digital-analog converters from the values of the parameters from the parameter setting unit and the output values in the storage unit; and a voltage value setting unit for setting, for the digital-analog converters, voltage values to be outputted from the digital-analog converters on the basis of the result of calculation by the arithmetic operation unit.

Pulse pattern generating apparatus

In an optical packet processing apparatus, an optical coupler joins optical packets transmitted through a plurality of input side optical transmission lines and outputs the joined optical packets to an output side optical transmission line. The optical packet processing apparatus has delay sections for delaying desired optical packets for each input side optical transmission lines. Delay times of the delay sections are different by one optical packet time period, while a minimum delay time thereof is the optical packet time period or more.

Optical packet processing apparatus

An optical switch changes over transmission paths of an optical signal by a refractive index change. The optical switch has an optical waveguide layer having an optical waveguide whose output path of an optical signal branches into two, and reflection diffusing ditches which are provided in a portion outside the optical waveguide in the optical waveguide layer, wherein the portion is closed to a branch portion of the optical waveguides. The reflection diffusing ditches extend in a direction crossing a traveling direction of the optical signal.

Optical switch

An optical switch in which the adverse effect of heating can be restrained is realized. An optical switch for switching a transmission path of an optical signal by a change in refractive index due to carrier injection comprises: a semiconductor substrate; an optical waveguide layer which is formed on the semiconductor substrate and in which an optical waveguide is formed, the optical signal being incident on the optical waveguide from one side, then branched into two at a halfway part and emitted from the optical waveguide; a first electrode formed on the optical waveguide layer and at a branching part of the optical waveguide; a second electrode formed on the optical waveguide layer and near the branching part of the optical waveguide; and a third electrode formed on the optical waveguide layer and on a side opposite to the first electrode as viewed from the second electrode; wherein when the optical switch is on, carriers are injected from the first and second electrodes, and when the optical switch is off, carriers are injected from the second and third electrodes.

An optical router for selecting optical paths for optical signals and outputting the optical signals. The optical router includes an optical delay device to delay the optical signals containing routing information in a header. An optical switch having input ports' and output ports receives optical outputs that are input from the optical delay device and outputs the optical signals. An optical-electrical conversion device converts the optical signals to electrical signals. A memory stores paths control information. A controller finds the path control information according to routing information output from the optical-electrical conversion device, determines destinations of the optical signal, and selects and assigns an input port in sequence from at least one input port having an output request to the output ports according to results of sorting a plurality of the output ports in ascending order of a number of output requests from the input ports.

Optical router

An inspection apparatus inspects an inspected object based on a waveform quality of a signal that the inspected object outputs. The inspection apparatus has a power supply section which outputs a control signal that controls an output of the inspected object, a waveform measuring section which measures the signal that the inspected object outputs to generate a waveform image, an analyzing section which derives a value indicating a waveform quality from the waveform image that the waveform measuring section measures, a deciding section which decides whether or not the value derived by the analyzing section satisfies a target value, and an optimizing section which changes a set value of the control signal that the power supply section outputs, based on a decision result of the deciding section.

Inspection apparatus

A photoelectric apparatus has a phototransistor which receives a light signal and in which a collector current thereof varies according to intensity of the received light signal, and a transistor in which a collector current thereof varies according to a base voltage thereof. The phototransistor and the transistor constitute a differential amplification circuit. At least one of the phototransistor and the transistor outputs an electric signal.

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Tokyo, Japan

Chie Sato