Abstract: An optical variable attenuator has a planar waveguide, which is provided with optical waveguides forming an input optical line A and an output optical line B. A cantilever is disposed at the upper face of the planar waveguide, whereas a movable mirror for reflecting light passing through the input optical line A toward the output optical line B is secured to the leading end part of the cantilever. An electrode is disposed at the upper face of the planar waveguide. The cantilever and the electrode are connected to each other by way of a voltage source. The voltage source applies a voltage between the cantilever and the electrode, so as to generate an electrostatic force therebetween, which flexes the leading end side of the cantilever toward the electrode. As a consequence, the movable mirror moves toward the electrode.

Abstract: A bumper structure extending over a width of a vehicle body is disclosed. The bumper structure includes a bumper face attached to the vehicle body, and upper and lower shock absorbers interposed between the vehicle body and the bumper face so as to have the lower shock absorber below the upper shock absorber. Crash stroke of the upper shock absorber is larger than that of the lower shock absorber. This bumper structure prevents a pedestrian from being damaged when the vehicle contacts the pedestrian, by generating an upward rotational force applied to the pedestrian.

Abstract: An interleaver is provided with an optical system configured to split light having traveled from a first port to a half mirror, into two beams and direct the beams toward first and second reflectors, respectively. Light reflected by the first reflector and arrived at the half mirror is split into two beams and directed toward second and third ports, respectively. Light reflected by the second reflector and arrived at the half mirror is split into two beams directed toward the second and third ports, respectively. An etalon filter configured to cause a loss on either one of light incident thereto from the first port and the beams directed toward the second port and toward the third port.

Abstract: A transmitted type diffractive optical element comprises a transparent plate made of a material having a refractive index n2, whereas the transparent plate is in contact with a medium having a refractive index n1. A number of projections are arranged with a period L on the first surface side of the transparent plate. Each projection has a rectangular cross section with a height H and a width W. An antireflection layer is formed on the second surface of the transparent plate. When the light L1 having a wavelength &lgr; is incident on the first surface at an incident angle &thgr;, the transmitted type diffractive optical element satisfies (2n1L/&lgr;)sin &thgr;=1, and n2/n1≦3 sin &thgr;, whereas each of the diffraction efficiencies of transmitted first-order diffracted light L31 in TE and TM polarization modes is at least 0.8.

Abstract: An object of the present invention is to provide a fixing structure for an optical element, which structure enables easy adjustment of a direction of the optical element when the optical element is fixed to a substrate. In order to achieve this object, a fixing member 31 made of metal is fixed to a substrate such that the fixing member holds an optical element therein and the bottom surface of the fixing member is spherical so that the spherical bottom surface touches the edge of the opening of a fixing portion on the substrate. The fixing member holds the optical element. A part of the surface of the fixing member is spherical such that the spherical part of the surface touches the edge of the opening of a fixing portion on the substrate. An optical device in which an optical element is fixed to a substrate with the fixing member mentioned above is also provided.

Abstract: A first optical system (11) has a first beam splitter (211). The first beam splitter (211) splits light arriving through a first optical path (P1) into two light beams, and outputs one light beam to a second optical path (P2) and the other light beam to a third optical path (P3). A second optical system (21) outputs the light output from the first beam splitter (221) to the second optical path (P2) and arriving at the second optical system (21) upon giving the light an intensity change with wavelength dependence and a phase change, and has a second beam splitter (221), first reflecting mirror (223), and second reflecting mirror (222). This makes it possible to provide an optical filter (200) which can realize a characteristic excellent in isolation with a very simple arrangement.

Abstract: The light which is input from an optical fiber to a first port is output to an optical path. The light which is input from the optical path to a half mirror is branched into two, and is output to the optical paths. The light which is output to the optical path reaches to and is reflected from a first reflecting mirror, and returns to the half mirror by an optical path. The light which is input to the half mirror by the optical path is branched into two, and is output to the optical paths. The light which is output to the optical path reaches to and is reflected from a second reflecting mirror, and returns to the half mirror by an optical path. The light which is input to the half mirror by the optical path is branched into two, and is output to the optical paths. The light which is output to the optical path is output from a second port to an optical fiber, and the light which is output to the optical path is output from a third port to an optical fiber.

Abstract: In order to make possible a variety of database searches, image data is registered on a first hard disk and a plurality of attribute tables each containing attribute information regarding images are registered on a second hard disk. When one search condition has been applied, a search of attribute information is conducted using one attribute table conforming to the search condition from among the attribute tables stored on the second hard disk. When another search condition has been applied, a search of attribute information is conducted using another attribute table stored on the second hard disk. Thus, a database can be searched even when search conditions differ.

Abstract: A diffraction grating device according to the present invention is a diffraction grating device in which a diffraction grating based on perturbation of refractive index is formed through a predetermined range in a light guide direction in an optical waveguide and in which the diffraction grating selectively reflects light in a reflection band out of light guided through the optical waveguide. In the diffraction grating device, the reflection band is divided into K (K≧2) wavelength bands, and the perturbation of refractive index &Dgr;nall in the predetermined range is represented by the sum of index perturbations &Dgr;nk (k=1−K) of periods &Lgr;k according to the respective K wavelength bands. Furthermore, at least one set of phases out of phases &phgr;k (k=1−K) of the index perturbations &Dgr;nk at a center position of the predetermined range are different from each other.

Abstract: An optical module has a planar waveguide which is provided with an optical circuit for an optical switch formed by 2×2 cross optical waveguides A1 to D1 and an optical circuit for an optical variable attenuator formed by 2×2 cross optical waveguides A2 to D2. Joined onto the planar waveguide is an actuator structure and the actuator structure is constituted by an actuator section for an optical switch and an actuator section for an optical variable attenuator. The optical circuit of the planar waveguide and the actuator section constitute an optical switch, whereas the optical circuit of the planar waveguide 2 and the actuator section constitute an optical variable attenuator.

Abstract: An optical variable attenuator has a planar waveguide, which is provided with optical waveguides forming an input optical line A and an output optical line B. A cantilever is disposed at the upper face of the planar waveguide, whereas a movable mirror for reflecting light passing through the input optical line A toward the output optical line B is secured to the leading end part of the cantilever. An electrode is disposed at the upper face of the planar waveguide. The cantilever and the electrode are connected to each other by way of a voltage source. The voltage source applies a voltage between the cantilever and the electrode, so as to generate an electrostatic force therebetween, which flexes the leading end side of the cantilever toward the electrode. As a consequence, the movable mirror moves toward the electrode.

Abstract: An optical filter has a first long-period grating and a second long-period grating formed in a unitary optical fiber. A difference is not less than 100 nm between a wavelength at which optical coupling is maximum between core-mode light and cladding-mode light of a predetermined mode number in the first long-period grating and a wavelength at which optical coupling is maximum between core-mode light and cladding-mode light of the same mode number as the cladding-mode light of the predetermined mode number, in the second long-period grating. This optical filter can be constructed in compact size and can readily implement a desired transmission characteristic.

Abstract: Light output from the distal end of an optical fiber collimator is input to a first diffraction grating formed on a first surface of a transparent member, and diffracted by the first diffraction grating at angles corresponding to wavelengths, and thus wavelength-branched. The light components of the respective wavelengths branched by the first diffraction grating and having propagated through the transparent member, are diffracted by a second diffraction grating formed on a second surface of the transparent member, and output from the transparent member. Each of the light components of the respective wavelengths, which are diffracted by the second diffraction grating and output from the transparent member, is input to the distal end of a corresponding one of optical fiber collimators, focused, and propagates through the optical fiber.

Abstract: A hologram recording medium comprises a hologram recording layer for recording a hologram, and a wedge substrate for varying the propagating direction of a reference light and an object light incident upon the hologram recording medium. By rotating the hologram recording medium comprising the hologram recording layer and the wedge substrate, the propagating direction of the reference light and the object light are varied, whereby angle multiplex recording of holograms can be realized with ease.

Abstract: An optical signal processing apparatus has a diffraction grating element, first condenser lens, Faraday rotation elements, polarization beam splitter, &lgr;/2 plate, second condenser lens, third condenser lens, and diffraction grating element. The magnitude of a magnetic field of each of the Faraday rotation elements is controlled on the basis of an externally input control signal. The rotation angle of the plane of polarization of signal light is set to 0 or &lgr;/2 in accordance with the magnitude of the magnetic field. Each Faraday rotation element receives signal light having wavelengths &lgr;1 to &lgr;4, which has arrived from the first condenser lens, and outputs the signal light as a polarized light component in the first azimuth (parallel to the z-axis direction) or second azimuth (parallel to the y-axis direction).

Abstract: This invention provides an optical signal processing apparatus capable of size reduction. When signal light with multiple wavelengths &lgr;1 to &lgr;4 is collimated by and output from a fiber collimator, the signal light components with multiple wavelengths &lgr;1 to &lgr;4 are diffracted by a diffraction grating at diffraction angles corresponding to the wavelengths and separated for the respective wavelengths. The separated signal light components of the respective wavelengths are output to spatially different optical paths. The signal light components having the wavelengths &lgr;n are deflected at their optical paths by prisms to increase the optical path interval and then input to fiber collimators.

Abstract: The present invention relates to an interleaver and others with a transmission spectrum excellent in isolation between signal channels and flat near each channel wavelength. The interleaver is provided with an input port for receiving a signal of multiple channels, and first and second output ports for outputting signals of first and second channel groups, respectively, separated from the signal of multiple channels. Each of transmission spectra of output light from the first output port and output light from the second output port has such flatness that a difference between a maximum transmittance and a minimum transmittance in a wavelength range of ±0.06 nm centered about each signal channel wavelength falls within 0.4 dB, preferably within 0.2 dB, and crosstalk between adjacent signal channels is controlled to −20 dB or less, preferably to −30 dB or less.

Abstract: Light entering a first port is incident to an etalon filter, suffers a loss according to a loss characteristic of the etalon filter, and is fed into a first optical path. The light incident through the first optical path to a half mirror is split into two beams and the beams are fed into a second optical path and a third optical path. The beam fed into the second optical path travels forward and backward between the half mirror and a first reflector to return to the half mirror. The beam incident to the half mirror is split into two beams and the beams are fed into a fourth optical path and a fifth optical path. The beam fed into the third optical path travels forward and backward between the half mirror and a second reflector to return to the half mirror. The beam incident to the half mirror is split into two beams and the beams are fed into the fourth optical path and the fifth optical path.

Abstract: The light which is input from an optical fiber to a first port is output to an optical path. The light which is input from the optical path to a half mirror is branched into two, and is output to the optical paths. The light which is output to the optical path reaches to and is reflected from a first reflecting mirror, and returns to the half mirror by an optical path. The light which is input to the half mirror by the optical path is branched into two, and is output to the optical paths. The light which is output to the optical path reaches to and is reflected from a second reflecting mirror, and returns to the half mirror by an optical path. The light which is input to the half mirror by the optical path is branched into two, and is output to the optical paths. The light which is output to the optical path is output from a second port to an optical fiber, and the light which is output to the optical path is output from a third port to an optical fiber.

Abstract: The invention relates to a temperature-compensated optical communication interference device. In this device, an optical divider divides light entering an input port into two light beams. An optical coupler superposes these beams and feeds the superposed light to an output port. First and second optical paths are provided between the divider and the coupler. First and second optical components are placed on the first and second optical paths, respectively. The divider, coupler, and optical components are placed on a substrate. The substrate has members with coefficients of linear expansion having different signs. Temperature dependence of an optical path length difference between the first and second paths is reduced due to the difference between the signs of the coefficients.