Yokogawa Electric Corporation

Katsuya Ikezawa

Akira Miura

Tsuyoshi Yakihara

Shinji Iio

Morio Wada

Chie Sato

Shinji Kobayashi

Akira Toyama

Sadaharu Oka

Masayuki Suehiro

Daisuke Hayashi

Hirotoshi Kodaka

Hiroshi Sugawara

Toshiaki Kobayashi

Shinichi Nakajima

Yoshiyuki Asano

Yasukazu Akasaka

Mamoru Hihara

Kenji Uchida

Tadashige Fujita

Machio Dobashi

Toshimichi Suzuki

Hiroyuki Matsuura

Takahiro Kudo

Takashi Mogi

Shin-ichi Nakajima

Toshimasa Umezawa

Hiroshi Shimizu

Shoujirou Araki

Minoru Akutsu

Tetsuya Ohtani

Kousuke Doi

Yusuke Kishine

Naoaki Machida

Shigeo Uneme

Kanji Tatsumi

A clock recovery apparatus for generating a recovery clock from received data may include, but is not limited to, first and second oscillators. The first oscillator generates a first signal having a first frequency. The first signal synchronizes with the received data when the received data has a first level. The second oscillator is connected in series to the first oscillator. The second oscillator generates a second signal as the recovery clock when the first signal has a second level. The second signal has a second frequency. The second signal synchronizes with the first signal.

Clock recovery apparatus

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

In a light modulating apparatus of an external modulating type which is used in an optical communication system, there are provided an LN modulator, a light branching circuit, a photoelectric converter, a bias control circuit, a driver for an LN modulator which serves to drive the LN modulator in response to an input electric signal, a capacitor for cutting off DC and low frequency components of the input electric signal, a low frequency component compensating circuit for compensating the DC and low frequency components of the input electric signal, and an adding circuit for adding an output of the bias control circuit and that of the low frequency component compensating circuit and generating a bias control signal of the LN modulator.

Light modulating apparatus

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

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 optical logic device performs a logic operation on a plurality of input light signals. The optical logic device has a photoelectric conversion portion, in which photoreceivers for receiving input light signals are provided in parallel, that outputs an electric signal obtained by adding up outputs of the photoreceivers, and a comparator that compares a voltage level of the electric signal outputted from the photoelectric conversion portion with a predetermined voltage level.

Optical logic device responsive to pulsed signals

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

A light modulation apparatus including a Mach-Zehnder type light modulator, a driver for modulator outputting a control signal according to an input electric signal, a light branching circuit branching the output light signal, and a bias control circuit applying a bias voltage to the light modulator based on the branched light signal, the apparatus further comprises: a burst pause state detection circuit detecting a pause state of a burst signal included in the input electric signal; a photoelectric transducer converting an output light signal branched by the light branching circuit into an electric signal; a sampling circuit extracting the electric signal converted while the pause state is detected by the burst pause state; and a bias voltage adjustment circuit adjusting a bias voltage value of the bias voltage based on a voltage level of the extracted electric signal.

Light modulation apparatus and light modulator control method

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.

Photoelectric conversion apparatus and photoelectric conversion system using the same

An optical switch has an input port, output ports, optical waveguides whose output path of an optical signal branch into two. A first stage optical switch section is provided in a branching portion of the optical waveguide, which switches a propagating path of an optical signal to a path leading to the desired output port. A subsequent stage optical switch section is provided in a branching portion of the optical waveguide subsequent to the first stage optical switch section, which switches a propagating path of a leakage light, which is leaked from the first stage optical switch section, to a path which does not propagates the leakage light to any of the output ports. The first stage optical switch section and the subsequent stage optical switch section switch a path of an optical signal according to a refractive index change caused by a carrier injection.

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Tokyo, Japan

Katsuya Ikezawa