Abstract: An optical device has first and second non-parallel optical paths, and a light reflecting surface. The reflecting surface may have a first and second planar portion. The first planar portion receives light from the first path to reflect the light toward the second path. The second planar portion may form an angle ?1 with the first planar portion. Angle ?1 satisfies a condition of 175°??<180° in either clockwise or counterclockwise rotation from the first planar portion.

Abstract: The present invention relates to an optical component and the like having a structure that can increase the absolute value of the angular dispersion, and also can reduce the temperature dependence of the diffraction angle. The optical component comprises a diffraction grating element of a transmissive type and a prism. The prism is composed of a material with a refractive index of n1, and the diffraction grating element and the prism are surrounded a material with a refractive index of n0.

Abstract: The present invention relates to 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, where a first band is defined as a band with a maximum bandwidth out of continuous wavelength bands for which the transmittance is not more than T0 and where a second band is defined as a wavelength band between a maximum wavelength and a minimum wavelength out of wavelengths for which the reflectance is R0, T0 is not more than ?20 dB and R0 is not more than ?20 dB. A ratio (B1/B2) of a width B1, of the first band to a width B2 of the second band is not less than 0.3. A maximum group delay difference caused by reflection of the light in the first band by the diffraction grating is not more than a predetermined limit, 0.

Abstract: There is disclosed an optical switch for switching between a plurality of main light emitters respectively emitting light components having wavelengths different from each other and a backup light emitter adapted to replace any of the main light emitters, a light emitter switching method for switching from one failed main light emitter to a backup light emitter by using the optical switch the above switch and a light receiver switching method for switching from one failed main light receiver to a backup light receiver by using the above.

Abstract: The ferrule part 16 comprises ferrule 60, first and second optical fibers 62 and 64, and optical filter 68. Ferrule 60 has first and second end surface 60a and 60b, ferrule insertion hole 60c, and groove 68. Ferrule insertion hole 60c extends along a first axis, and accommodates first and second optical fibers 62 and 64. Groove 66 extends along a second axis crossing the first axis, and extends so as to extend across ferrule 60. Groove 66 is provided along a plane defined by the second axis and a third axis perpendicular to the first and second axes. Optical filter 68 can reflect a part of light incident on one surface 68b of the pair of surfaces of optical filter 68, and can transmit a part of the light incident on other surface 68a.

Abstract: In an optical transmitter in which the amount of light of an LD is monitored by a monitor PD, and the power of the LD is kept constant by feedback, the present invention aims to provide an optical transmitter that is suitable for size and cost reductions while being able to input a greater amount of the LD light of to the monitor PD, and that is capable of performing higher-bit-rate transmission. The present invention is characterized in that a concave groove is formed in a substrate, and the monitor photodiode is mounted on a slanted face of the concave groove, and the light of the LD that is oppositely and horizontally disposed is received directly by the monitor the LD photodiode.

Abstract: A semiconductor light receiving element has a semiconductor portion. The semiconductor portion includes a substrate, a light detecting portion, and a filter portion. The substrate, the light detecting portion, and the filter portion are provided sequentially in a direction of a predetermined axis. The light detecting portion has a light absorbing layer including a III-V semiconductor layer, a window layer including a III-V semiconductor layer, and an anode semiconductor region. The light absorbing layer is an n or i conductivity type semiconductor layer. The light absorbing layer is provided between a III-V semiconductor layer and the window layer. The light detecting portion is provided on one face of the semiconductor substrate with the III-V semiconductor layer interposed therebetween. The filter portion includes InGaAsP semiconductor layers and III-V semiconductor layers.

Abstract: [Problem] Provided is a diffraction grating element that allows the temperature control mechanism to be dispensed with or simplified.

Abstract: A ferrule product 30b is utilized in an optical module 5 comprising a semiconductor optical amplifier 55 having a pair of end facets. The ferrule product 30b comprises an optical fiber 51 and a ferrule 52. The optical fiber 51 has one end part, optically coupled with one of the pair of end facets, a first part including a grating 511 disposed at a predetermined position separated from one end part, and a second part different from the first part. The ferrule 52 has a capillary part 521 for holding the optical fiber 51 and a flange part 522 for holding the capillary part. The flange part 522 is disposed on the second part.

Abstract: The present invention relates a diffraction grating element capable achieving a large angular dispersion and excellent diffraction characteristics. The diffraction grating element has a buried structure, and comprises: a first medium with a refractive index of n1; a second medium with lower refractive index of n2 than the first medium; and a diffraction grating formed at the interface between the first and second mediums. One of the first and second mediums is a solid, and the other thereof is a solid or a liquid. An anti-reflection film is formed on one surface of the first medium 11 on which the diffraction grating is not formed, and this anti-reflection film lies in contact with a medium with a refractive index no. Furthermore, an anti-reflection film is also formed on one surface of the second medium on which the diffraction grating is not formed, and this anti-reflection film lies in contact with the medium with the refractive index no.

Abstract: An optical switch that can restrain the occurrence of cross talk is provided. A first waveguide path 11 and a second waveguide path 12 are provided on a waveguide substrate PCL so as to intersect each other at a given angle. A trench T is formed in a straight line in the surface of the waveguide substrate PCL so as to cross the central axes of the first waveguide path and the second waveguide path. The trench T is as deep as to expose the whole end face of the first waveguide path and the second waveguide path. The first waveguide path 11 and the second waveguide path 12 are arranged such that their central axes are arranged asymmetrically with respect to the straight line.

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: The present invention relates to an optical waveguide type grating element and others in structure for decreasing absolute values of chromatic dispersion occurring in selective reflection of each of signal channels in a reflection band. The optical waveguide type grating element is provided with an optical waveguide in which signal light containing a plurality of signal channels spaced at a channel spacing &lgr;i propagates, and a grating which is an index modulation formed over a predetermined range of the optical waveguide. Particularly, the optical waveguide type grating element has a transmittance of −20 dB or less for each of the signal channels in the reflection band, and has a reflectance of −20 dB or less for each of signal channels outside the reflection band. Furthermore, a deviation of a group delay time of each of the signal channels in the reflection band, which is caused by reflection in the grating, is 10 ps or less in a wavelength range of (&lgr;CH−&lgr;i×0.

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: There is disclosed an optical switch for switching between a plurality of main light emitters respectively emitting light components having wavelengths different from each other and a backup light emitter adapted to replace any of the main light emitters, a light emitter switching method for switching from one failed main light emitter to a backup light emitter by using the optical switch the above switch and a light receiver switching method for switching from one failed main light receiver to a backup light receiver by using the above.

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: The ferrule part 16 comprises ferrule 60, first and second optical fibers 62 and 64, and optical filter 68. Ferrule 60 has first and second end surface 60a and 60b, ferrule insertion hole 60c, and groove 68. Ferrule insertion hole 60c extends along a first axis, and accommodates first and second optical fibers 62 and 64. Groove 66 extends along a second axis crossing the first axis, and extends so as to extend across ferrule 60. Groove 66 is provided along a plane defined by the second axis and a third axis perpendicular to the first and second axes. Optical filter 68 can reflect a part of light incident on one surface 68b of the pair of surfaces of optical filter 68, and can transmit a part of the light incident on other surface 68a.

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: The present invention relates to 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, where a first band is defined as a band with a maximum bandwidth out of continuous wavelength bands for which the transmittance is not more than T0 and where a second band is defined as a wavelength band between a maximum wavelength and a minimum wavelength out of wavelengths for which the reflectance is R0, T0 is not more than −20 dB and R0 is not more than −20 dB. A ratio (B1/B2) of a width B1, of the first band to a width B2 of the second band is not less than 0.3.

Abstract: A semiconductor light receiving element has a semiconductor portion. The semiconductor portion includes a substrate, a light detecting portion, and a filter portion. The substrate, the light detecting portion, and the filter portion are provided sequentially in a direction of a predetermined axis. The light detecting portion has a light absorbing layer including a III-V semiconductor layer, a window layer including a III-V semiconductor layer, and an anode semiconductor region. The light absorbing layer is an n or i conductivity type semiconductor layer. The light absorbing layer is provided between a III-V semiconductor layer and the window layer. The light detecting portion is provided on one face of the semiconductor substrate with the III-V semiconductor layer interposed therebetween. The filter portion includes InGaAsP semiconductor layers and III-V semiconductor layers.