Oki Electric Industry Co., Ltd.

Yutaka Okabe

Yoichi Nishioka

Hiroyo Kato

Hideaki Okayama

Hironori Sasaki

Yukihisa Okada

A wavelength conversion element with a Quasi-Phase Matching structure which can suppress the ripples of fluctuation pulse waveforms of a change efficiency in a frequency band of the waveform conversion, without controlling the positions and dimensions of the polarization regions at high precision. The wavelength conversion element of the present invention has a plurality of first and second polarization regions, formed so that dielectric polarizations are inverted from each other, and an optical wave guide which is formed so as to pass through the first and second polarization regions, in a nonlinear optical substrate. And an absolute value of the wavelength conversion efficiency is set by adjusting the positional coordinates of the first and second polarization regions in a light traveling direction.

Wavelength conversion element with quasi-phase matching structure

An optical demultiplexer/multiplexer for wavelength division multiplex communication includes: a light irradiating unit for irradiating a spherical wave containing light waves of different wavelengths; optical fibers for respectively receiving the different wavelengths of the demultiplexed light wave; a converting lens for receiving the spherical wave and converting the spherical wave into a parallel wave; WDM filters each for selecting and reflecting the light wave in the parallel wave and transmitting the residual light waves; guide lenses for receiving the light waves reflected by the WDM filters, converging, and transmitting the light waves to the optical fibers; and reflecting mirrors for receiving the light waves and reflecting the light waves toward the WDM filters. The parallel wave advances from the converting lens, is selected and reflected by the WDM filter, reflected, returned to the WDM filter, selected and reflected again, converged by the guide lens, and demultiplexed by the optical fiber every wavelength.

Optical demultiplexer and optical multiplexer for wavelength division multiplex communication

A thermoreversible recording material having its transparency changed in accordance with its thermal history, in particular the rate of cooling and the temperature to which it has been heated, comprises a matrix material and an organic compound of low molecular weight, wherein the matrix material comprises polyvinyl acetal, and the organic compound of low molecular weight comprises a saturated carboxylic acid or derivative thereof. The matrix material may further contains a material selected from a group consisting of epoxy resin, phenol resin, epoxy compound, aldehyde compound and isocyanate compound. A thermoreversible recording medium comprising the above thermoreversible recording material may be selectively heated by a thermal head or the like to record visual information. The visual information may be erased by heating the medium and cooling it slowly.

Thermoreversible recording material, thermoreversible recording medium

An image recording device which permits repeated thermoreversible recording and erasure of an image, which is useful for creating an image for storage, display or printing of the image or other information. The recording device has a display medium, a recording means to form an image on the display medium, and an erasure means to erase the image formed on the medium. The display medium of the image recording device may have a support member with a recording layer provided on the support member. The display medium has a transparency which is dependent upon its thermal history, and consists essentially of a matrix material of a copolymer of styrene and butadiene, and a saturated carboxylic acid of 10 to 24 carbon atoms. The weight ratio of the matrix material to saturated carboxylic acid in the display medium is from 1:1 to 20:1.

Thermoreversible recording medium, apparatus utilizing the same and

An image forming apparatus which permits reversible recording and erasure by a heating means, and permits storage, display, printing or reproduction of an image or other information. The present apparatus thermoreversibly records an image on a matrix material of a copolymer of styrene and butadiene and a low molecular weight, saturated carboxylic acid, preferably containing from 10 to 24 carbon atoms, and where the weight ratio of the matrix material to carboxylic acid is from 1:1 to 20:1.

A thermoreversible recording medium which permits reversible recording and erasure to be repeated by use of a heating means, such as a thermal head or a laser, and is used for example, for storage, display or printing of image or other information, comprises a matrix material and an organic substance of low molecular weight. The matrix material essentially consists of a copolymer of styrene and butadiene, and the organic substance is a saturated carboxylic acid. The saturated carboxylic acid may preferably be capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachic acid, behenic acid or lignoceric acid. These compounds are saturated carboxylic acids with 10-24 carbon atoms. The weight ratio between the matrix and the organic substance is set within 1:1 to 20:1.

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Tokyo, Japan

Yutaka Okabe