Abstract: In a polarized wave interleaver 100, signal light of a first wavelength band ?1 of polarized light component in a first orientation, which enters an input port 111, proceeds to a first path P1 through a first polarized wave separation element 131. Even after passing through a wavelength filter 140, the polarized light component in the first orientation is maintained as it is. And the light proceeds to a third path P3 through a second polarized wave separation element 132, and is output from a first output port 121. Signal light of a second wavelength band ?2 of polarized light component in a second orientation, which enters the input port 111, proceeds to a second path P2 through the first polarized wave separation element 131, and is converted to the polarized light component in the first orientation by the wavelength filter 140. And the light proceeds to a fourth path P4 through the second polarized wave separation element 132, and is output from a second output port 122.

Abstract: The present invention relates to an optical signal processor which can multiplex or demultiplex multiwavelength signal light. The optical signal processor includes an optical input/output capability, a first optical system, a wavelength branching capability, a second optical system, and a reflecting capability.

Abstract: The present invention relates to an optical multiplexer/demultiplexer. In the multiplexer/demultiplexer, a first grating receives to diffract a multi-wavelength light signal from a first port into light signals with different wavelengths. A second grating diffracts these light signals towards second ports. The second grating is disposed parallel with the first grating. The second grating has the same grating interval and grating direction as the first grating. The light signals diffracted by the second grating travel parallel with each other. Therefore, the light signals can efficiently enter the second ports without sophisticated lens design and adjustment of the optical system.

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: 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: [Problems to be solved] To provide an optical switching device which can switch between input/output optical paths of input/output ports while suppressing the influence on optical signals passing through other input/output ports.

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: An optical signal processor comprises fiber collimators, a first diffraction grating device, a second diffraction grating device, a first half-wave plate, and a second half-wave plate. Each of the diffraction grating devices is of reflection type having a diffracting surface parallel to a yz plane and a grating direction parallel to a z axis. The diffraction grating device diffracts the light outputted from the fiber collimator after collimation. The diffraction grating device diffracts the light diffracted by the diffraction grating device. The half-wave plates having respective optic axes in directions different from each other by 45 degrees are bonded together and are disposed on an optical path between the diffraction grating devices.

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: An optical element comprises optical input/output means, polarization separating means, polarization plane rotating means, wavelength branching means, a condenser optical system, and reflecting means. The optical input/output means, for inputting and outputting light, has a plurality of ports. The polarization separating means separates the light into respective polarized light components (first and second light beams) having first and second directions orthogonal to each other. The polarization plane rotating means rotates a polarization direction of the received light beam to make the first and second light beams have the same polarization direction. The wavelength branching means spatially separates the light beams in terms of wavelength, and outputs thus separated wavelength light components. The condenser optical system converges the wavelength light components.

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: An optical signal processor comprises optical input/output means, a first optical system, wavelength branching means, a second optical system, and reflecting means. The optical input/output means includes a plurality of input/output ports. The ports have respective light input/output directions, in parallel with each other, located on a first virtual plane. The optical input/output means inputs light into any of the ports and outputs the light from any of the ports. The first optical system collimates the light. The wavelength branching means spatially separates the light in terms of wavelength, and outputs thus obtained wavelength light components. The wavelength light components have respective optical axes located on a second virtual plane. The second optical system receives the wavelength light components and converges them. The reflecting means includes a mirror with a reflecting surface positioned at a light-converging point of the wavelength light components converged by the second optical system.

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: An object of the present invention is to provide an optical device that can restrain the dependence of the center wavelength of reflection at the diffraction grating upon the voltage applied to the piezoelectric element from shifting depending on the temperature. An embodiment of the optical device has the following structure.

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: 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.