Nippon Telegraph and Telephone Corporation

Ntt Advanced Technology Corporation

Hamamatsu-photonics K.k.

Nippon Telephone and Telegraph Corporation

Nippon Telegraph and Telephone Communications

Shogo Yagi

Tadayuki Imai

Kazuo Fujiura

Seiji Toyoda

Masahiro Sasaura

Makoto Abe

Takashi Kurihara

Koji Enbutsu

Eishi Kubota

Jun Miyazu

Yoshiaki Kurokawa

Takashi Sakamoto

Masahiro Endo

Kazunori Naganuma

Takaya Tanabe

Yuzo Sasaki

Eiichi Sugai

Takeshi Watanabe

Hiroshi Yoshikawa

Kazuhito Higuchi

Masahiro Ueno

Manabu Yamamoto

Koei Yamamoto

Saburo Imamura

Satoru Tomaru

Masatoshi Fujimoto

Kazuto Noguchi

Yuichi Okabe

Noboru Sonehara

Tsutomu Horikoshi

Tadashi Sakamoto

Makoto Hikita

Takaaki Akimoto

Tetsuyoshi Ishii

Akiyuki Tate

Joji Yamaguchi

Haruki Kozawaguchi

Kazutoshi Kato

Haruhiko Kojima

Shigeo Ishibashi

Akinori Furuya

Toshifumi Ohkubo

Koji Yoneyama

Fumio Saito

Yukihiko Ushiyama

Koichiro Nakamura

Tohru Kodaira

Akira Sawaguchi

Hideki Hagino

Noriyuki Ishidu

Hiizu Takemura

Mahiro Yamada

Provided is a position locating instrument for a position locating method in which position locating instruments that transmit and receive light beams are arranged in series connection. The position locating instruments reduce error factors and improve measurement accuracy by providing all or some of necessary position and attitude parameters. The position locating instrument has at least one light emission port through which light from a wavelength-changeable light source is emitted; and at least one light receiving port that receives light emitted or reflected by an adjacent position locating instrument. The light emitted from the light emission port has a fanlike pattern and has an emission angle varying, as a monotonic function of a wavelength of the light, in a direction perpendicular to a direction in which the light spreads in the fanlike pattern.

Position locating instrument

Provided is a swept light source including one end surface coupled to a wavelength filter constituted of a diffraction grating and an end mirror via a light deflector and another end surface including a gain medium facing an output coupling mirror and which configures a laser cavity between the end mirror and the output coupling mirror, wherein a drive voltage having an AC voltage on which a DC bias voltage is superimposed is output from a control voltage source of the light deflector to an electrode pair of an electro-optic crystal, light is radiated from a light emitter to the electro-optic crystal, and incident light from the gain medium incident along an optical axis perpendicular to a direction of an electric field formed by the control voltage is deflected in a direction parallel to the electric field, so that wavelength sweeping is performed.

Swept light source and method for controlling the same

A wavelength swept light source includes a sawtooth waveform as a main waveform and an exponential component of the sawtooth waveform to the controlled voltage of the electro-optic deflector. The controlled voltage is controlled so that, as an oscillation wavelength to be swept is swept towards a longer wavelength side, a change rate of the oscillation wavelength is increased.

Wavelength swept light source

A variable focusing lens is provided that can change the focal length at a high speed. The variable focusing lens includes: a single crystal electrooptic material having inversion symmetry; a first anode formed on a first surface of the electrooptic material; a second cathode provided to have an interval to the first anode; and a first cathode and a second anode that are formed on a second surface opposed to the first surface and that are formed at positions opposed to the first anode and the second cathode. An optical axis is set so that, when light enters through a third face orthogonal to the first surface, light exists through a fourth surface opposed to the third face. A voltage applied between the first and the second pair of electrodes is changed to thereby change the focal point of light emitted from the fourth surface of the electrooptic material.

Variable focusing lens and microscope

The present invention provides a small spectroscope that has a short response time. A spectroscope according to one embodiment of the present invention includes: a beam deflector that includes an electro-optic crystal, having an electro-optic effect, and paired electrodes used to apply an electric field inside the electro-optic crystal; spectroscopic means for dispersing light output by the beam deflector; and wavelength selection means for selecting light having an arbitrary wavelength from the light dispersed and output by the spectroscopic means.

Spectroscope

To provide a variable-focal length lens capable of altering its focal length at high speed. The variable-focal length lens has an electrooptic material and electrodes formed on an incident surface of light and on an exit surface of the light of the electrooptic material. An optical axis is set so that the light is inputted into a gap where the electrodes of the incident surface are not formed and is outputted from a gap where the electrodes of the exit surface are not formed. A focus of the light that is transmitted through the electrooptic material becomes variable by varying an applied voltage between the electrodes of the incident surface and the electrodes of the exit surface.

Variable-focal length lens

An optical memory medium () has cores () each constituting a planar optical waveguide and clads () sandwiching each core, and has a data image () in which data is recorded as a scattering factor and a pair of positioning marks () which are scattering factors required for positioning at an interface between a core () and a clad () or in the core (). A read light () travels while spreading in the core () and scatters and interferes by the data image (), and data is reproduced from a data reproduction light () generated by this scattering and interference. A pair of positioning lights () are caused to enter the core () with offsets with respect to the read light () in opposite directions along a thickness direction of the core (), and scatter and interfere at the pair of positioning marks (). Incidence positions of the lights emitted from a light source () with respect to the core () in a thickness direction of the core () are controlled based on intensities of a pair of positioning mark lights () generated by this scattering and interference.

Optical memory reproduction apparatus and incidence positioning method for read light thereof

An information coding apparatus, an information decoding apparatus, and a method and a program therefor are provided, which can represent a large amount of information with a small number of pixels. Information bits which are inputted are coded as a block of a two-dimensional image made up from m (where m is a natural number)&#xd7;n (where n is a natural number) pixels. Specifically, pixels which represent the information bits are arranged in a code area, which is an area of (m&#x2212;o)&#xd7;(n&#x2212;p) pixels within a code block of m&#xd7;n pixels (where o and p are natural numbers which satisfy 0&#x3c;o&#x3c;m and 0&#x3c;p&#x3c;n); and, no pixels which represent the information bits are arranged in a guide area, which is an area of the other pixels within the code block of m&#xd7;n pixels.

Information coding apparatus, information decoding apparatus, and method and program for the same

An optical waveguide capable of having various characteristics and a method of manufacture thereof as well as a method of manufacturing a crystal film are provided. An optical functional material KTaNbOis used as an optical waveguide. The input optical signal is transmitted to the KTaNbOfilm. The KTaNbOfilm undergoes changes in optical property when an external voltage signal is applied to the electrode. Therefore, as it passes through the KTaNbOfilm, the input optical signal is modulated by the characteristic change. The modulated optical signal is taken out as an output optical signal.

Optical waveguide and method of manufacture

A wavelength converter implements high speed, high efficiency, low noise wavelength conversion without performing high voltage poling of a crystal, and enables switching and modulation of converted light in response to an electric field. A KLTN crystal, includes a deposited-gold electrode within its incidence plane, and is connected to a DC power supply via a copper wire. The crystal material is composed of KTa Nb O and/or K Li Ta Nb O . A polarizer controls the polarization of the fundamental wave in the direction parallel to the electric field, and launches it into the electrode of the KLTN crystal. The KLTN crystal, rotating on an axis in the direction of the electric field, launches only part of the generated SHG light with the same polarization direction as that of the incident light into a photo multiplier tube through a polarizer.

Wavelength converter

An optical waveguide capable of having various characteristics and a method of manufacture thereof as well as a method of manufacturing a crystal film are provided. An optical functional material KTa Nb O is used as an optical waveguide. The input optical signal is transmitted to the KTa Nb O film. The KTa Nb O film undergoes changes in optical property when an external voltage signal is applied to the electrode. Therefore, as it passes through the KTa Nb O film, the input optical signal is modulated by the characteristic change. The modulated optical signal is taken out as an output optical signal.

An information reading apparatus can detect the coupling state of the input light to a waveguide of a laminated recording medium in a simple manner, so as to enable to focus the input light on a target recording layer to access the information recorded in the target recording layer quickly. The apparatus is compact and is economical to produce. The apparatus has a light source for injecting a light on an input edge of a lamination recording section, assembled into the recording medium containing a lamination of recording layers. Each recording layer has data represented by scattering centers which diffract an input light generated by a converging lens. An input light directing device directs the light source and the converging lens as a unit to focus the input light on a desired location. An image recording device records an informational image generated by guided waves produced within a laminated waveguide. An optical power detector detects output light emitted from an output edge of a specific recording layer as well as scattered light generated from recording layers other than the specific recording layer. An optical power discrimination circuit determines whether an optical power detected by the optical power detector is associated with the output light or the scattered light. Data recorded in any specific recording layer can be accessed quickly and simply by focusing input light on a core layer of a multi-layered hologram recording data storage medium. Because the absolute positional information stored in the storage medium is minimized, data storage capacity of the storage medium is almost unaffected while making the apparatus compact and low cost.

Information reading apparatus and information recording medium

A laminated optical medium for read-only information recording has ultra-high memory capacity and reliably extracts desired information from laminated memories. Methods for low-cost mass production of laminated read-only medium are demonstrated. The optical medium is a lamination of planar type waveguides made of polymeric materials, in which each waveguide has information recorded as periodic scattering factor to generate scattered light by injection of input light into a waveguide layer. Therefore, read-only information recording medium of ultra-high memory capacity, equivalent to the memory capacity achievable by volume holography, can be produced by using a low-cost planar holographic technique. The laminated medium is simple and energy conserving, because it does not require rotation mechanisms for reproduction of music and video holographic recordings. The medium is ideally suited as identification card, because the card is difficult to counterfeit and a high level of extra information can be stored conveniently for use in a wide range of potential applications.

Read-only laminated information recording medium and manufacturing method therefor

A method and an apparatus for three-dimensional holographic display suitable for moving object display are disclosed. At least one hologram of a display target object is displayed on a display device, and a non-scattered light is irradiated onto the display device to produce a scattered light. Then the scattered light from the display device as an object light of the display target object and the non-scattered light as a reference light are irradiated simultaneously at different incident angles onto a photorefractive medium having a photorefractive effect, and interference fringes generated by the object light and the reference light are recorded in the photorefractive medium. Then, the three-dimensional image is displayed by irradiating only the non-scattered light onto the photorefractive medium so as to reproduce a holographic image corresponding to the interference fringes recorded in the photorefractive medium.

Method and apparatus for three-dimensional holographic display suitable for video image display

Growing community of inventors

Atsugi, Japan

Shogo Yagi