Canon Kabushiki Kaisha

Yasuo Tomita

Hitoshi Oda

Masaaki Shibata

Naosato Taniguchi

Kazuya Matsumoto

Masahiro Okuda

Shigetaro Ogura

Toshihiko Yoshino

Johan Bergquist

Disclosed are an optical interconnection network and process, having a phase-conjugate mirror and input and output side channels. In the network, time-reversed wave, of a light beam propagated through the output side channel, is generated in the phase-conjugate mirror to cause an interconnection between the input side channel and the output side channel. The energy of the time-reversed wave comes from a light beam propagated through the input side channel.

Optical interconnection networks and processes

A method of measuring the pulse width of a light pulse comprises the steps of causing a first light and a second light, which are both light pulse, to enter a medium having a two-photon absorption effect, detecting the first light of the first light and second light which have passed such medium, and measuring the pulse width of the first light or the second light on the basis of the result of the detection, and an apparatus for measuring the pulse width of a light pulse from a light source using this measuring method, whereby to obtain the self correlation function of light pulse of a light to be measured passing through the two-photon absorption medium for the provision of a highly precise measurement of light pulse width without any high precision phase adjustment of the light beam.

Apparatus for measuring pulse width using two-photon absorption medium

A light modulating apparatus includes a semiconductor device having a quantum well structure and a device for applying an electric field to the quantum well structure of the semiconductor device. Both of pump and probe light beams or a pump and probe light beam is input into the semiconductor device. The pump light beam or pump and probe light beam received by the semiconductor device causes a real charge excitation in the quantum well structure, and the real charge excitation screens the electric field applied to the quantum well structure. The polarization state of the probe light beam or pump and probe light beam emerging from the semiconductor device is changed by an electrooptical effect in the quantum well structure induced by the real charge excitation. A polarizer may be disposed for converting a change in polarization state of the light emerging from the semiconductor device into a change in intensity of the light.

All-optical light modulating apparatus and all-optical process for

In a polarization-state converting apparatus for use as an optical isolator, an optical modulator and the like, there are provided a waveguide including a magnetic semiconductor, a device for applying a magnetic field to the waveguide in a first predetermined direction, a device for applying an electric field to the waveguide in a second predetermined direction, and a mode conversion is caused via electrooptic and magnetooptic effects due to the electric and magnetic fields to change the polarization state of light propagating through the waveguide. When used as an optical isolator, the optical isolation is performed to compensate for degradation of the mode conversion rate due to a phase mismatch between light incident upon the waveguide and light emerging from the waveguide. When used as an optical modulator, the optical modulation of light emerging from the waveguide is performed by varying the electric field and an optical isolation function is effected while compensating for degradation of the mode conversion rate due to a phase mismatch between light incident upon the waveguide and light emerging from the waveguide.

Optical polarization-state converting apparatus for use as isolator,

An optical modulation apparatus includes a semiconductor element having a quantum well structure, a unit for applying an electric field to the quantum well structure of the semiconductor element, a unit for supplying polarized probe light to the semiconductor element, the probe light emerging from the semiconductor element such that a polarization state thereof is changed by an electrooptical effect in the quantum well structure, a unit for causing the semiconductor element to receive pump light which causes virtual charge excitation in the quantum well structure, the virtual charge excitation screening the electric field applied to the quantum well structure, and a polarizer for converting a change in polarization state of the light emerging from the semiconductor element into a change in intensity.

Method and apparatus for modulating light using semiconductor element

An optical logic operation apparatus includes an optical induction refractive index crystal having first and second planes parallel to each other and a device for inputting a coherent probe light from the first plane of the crystal. At least one of the first light output from the first plane of the crystal and the second light output from the second plane of the crystal is taken out so that one of the first and second lights is amplified by the two-wave coupling of the probe light reflected by the second plane and the probe light inputted from the first plane and the other light is attenuated likewise by the two-wave coupling. The inputted image is projected onto the crystal by use of light incoherent to the probe light. With the incidence of the incoherent light, a gain distribution corresponding to the inputted image is generated in the crystal so as to modulate the first and second lights spatially.

Method and apparatus for obtaining modulated light indicative of an

A light signal reading method in which a first light beam modulated to a polarized state in accordance with information magnetically recorded on a recording medium is caused to interfere with a second light beam of a frequency different from that of the first light beam, and the information being detected as a variation in the intensity of the interference light, and an apparatus therefor.

Light signal reading method and apparatus using interference between two

A magneto-optical recording medium is disclosed which comprises a substrate, a magnetic thin film and a multi-layered dielectric layer for regulating the reflection factor of the magnetic thin film.

Magneto-optical recording medium having alternately-layered high and low

This specification discloses a magneto-optical recording medium, comprising a substrate; a magnetic film formed on the substrate and having an axis of easy magnetization perpendicular to the film surface; and an arrangement for establishing a reflection factor of not more than 10% at the surface of the magnetic film.

Magneto-optical recording medium

A waveguide for propagating a light beam, a coupler for coupling the light beam to the waveguide, and a thin film layer provided on the bottom surface of the coupler and consisting of a substance having a refractive index lower than the refractive indices of the waveguide and the coupler, the coupler being joined to the waveguide by optical contact with the thin film layer interposed therebetween, together constitute an optical coupler device which is compact and stable in optical coupling characteristic.

Method of making an optical coupler device utilizing volatile liquid to

This specification discloses a magneto-optical information reading apparatus which comprises a device for causing a light beam polarized in a predetermined direction to enter a magnetic recording medium on which information is recorded, an analyzer provided in the optical path of the light beam modulated by the magneto-optic effect in accordance with the information, and a photodetector having the current amplifying function and photoelectrically detecting the light beam transmitted through the analyzer, and in which the following equation is substantially satisfied: ##EQU1## where .phi. is the transmission axis azimuth of the analyzer relative to the predetermined direction of polarization and .eta. is the extinction factor of the analyzer.

Magneto-optical information reading apparatus

A device for reading magnetically recorded patterns on a magnetic recording medium includes a first system for causing a light beam polarized in a predetermined direction to enter the recording medium, a second device for relatively varying the ratio of the polarized component in the predetermined direction and the polarized component in a direction perpendicular thereto, of the light of said light beam reflected or transmitted by the recording medium, and a third device including a photodetector and an amplifier for amplifying a detection signal, the third device being for detecting the light beam from the second means and reading the recorded patterns on the magnetic recording medium, the second device being set so that the SN ratio of the detection signal becomes maximum.

Growing community of inventors

Yokohama, Japan

Yasuo Tomita