Abstract: There is provided a novel halogenated zinc phthalocyanine pigment for a color filter, which can form a green color filter having excellent contrast and high luminance. A halogenated zinc phthalocyanine pigment for a color filter shows, in a Raman spectrum, a peak intensity of 3.0% or more at 716±2.2 cm?1 when a peak intensity at 650±10 cm?1 is regarded as 100%.

Abstract: A bidirectional optical module according to the present invention comprises light emitting elements 110, 130 that emit light to enter an optical fiber 71, a light receiving element 190 that receives light having exited the optical fiber 71 and a light branching element 160 that guides the light having exited the optical fiber 71 onto the light receiving element 190. It further includes a stray light shielding member 185 disposed between the light branching element 160 and the light receiving element 190 and having formed therein an opening 186, through which the light to enter the light receiving element 190 passes. The stray light shielding member 185 blocks stray light 100b while light 100a having exited the fiber 71 passes through the opening 186. Therefore, any increase in the extent of error in the detection of the returning light level or the position of a reflecting point is prevented.

Abstract: An improvement is made to a wavelength tunable light source of an external resonator type for selecting a wavelength of light from a semiconductor laser using a diffraction grating. The device has a prism provided between the semiconductor laser and the diffraction grating for enlarging the beam shape of the light from the semiconductor laser in the groove arrangement direction of the diffraction grating, emitting the light to the diffraction grating, and reflecting diffracted light from the diffraction grating to provide output light.

Abstract: A bidirectional optical module according to the present invention comprises light emitting elements 110, 130 that emit light to enter an optical fiber 71, a light receiving element 190 that receives light having exited the optical fiber 71 and a light branching element 160 that guides the light having exited the optical fiber 71 onto the light receiving element 190. It further includes a stray light shielding member 185 disposed between the light branching element 160 and the light receiving element 190 and having formed therein an opening 186, through which the light to enter the light receiving element 190 passes. The stray light shielding member 185 blocks stray light 100b while light 100a having exited the fiber 71 passes through the opening 186. Therefore, any increase in the extent of error in the detection of the returning light level or the position of a reflecting point is prevented.

Abstract: A tunable laser source that stably outputs high-output light with reduced spontaneous emission light is to be realized. This invention is an improvement of a tunable laser source of external resonator type. This apparatus comprises a wavelength selecting unit for selecting a wavelength of incident light and emitting the light of the selected wavelength, an optical amplifier unit for making light incident on the wavelength selecting unit from one end, and a mirror for reflecting light from the other end of the optical amplifier unit directly to the wavelength selecting unit. The wavelength selecting unit feeds the light from the one end of the optical amplifier unit back to the optical amplifier unit and emits the light from the mirror as output light.

Abstract: There is provided a wavelength tunable light source 10 in which one end surface 1a of a semiconductor laser 1 is applied anti-reflection film, a lens 6 collimates a light beam emitted from the one end surface 1a of the semiconductor laser 1 onto which the anti-reflection film is applied, and a wavelength selection portion constituted by a combination of a diffraction grating 2 and a mirror 3 selects a light beam having a desired wavelength to return the selected light to the semiconductor laser 1 to make laser oscillation. A center of rotation of the mirror 3 is provided in a position P0 where mode hopping can be suppressed when the wavelength is tuned and rotation of the mirror 3 is driven by a direct drive system by using a motor 4 having a rotation shaft 4a in the center of rotation of the mirror 3.

Abstract: A tunable filter includes a wavelength selector and a reflector. The wavelength selector selects a wavelength of a light beam. The reflector reflects the light beam, the wavelength of which is selected by the wavelength selector. The light beam reflected by the reflector is again introduced into the wavelength selector to improve wavelength selectivity.

Abstract: A light source for an external cavity laser comprises a semiconductor laser 1 having a first facet to which is applied an antireflection coating 1A and a second facet to which is applied a increased reflection coating 1B defining a predetermined reflectivity, lenses 5, 6, a diffraction grating 2, and a mirror 3, wherein a light emitted from the first facet is converted into a parallel light by the lens 5, and the parallel light passes through the diffraction grating 2 to select a wavelength and is reflected to the diffraction grating 2 by the mirror 3 to select a wavelength via the diffraction grating 2 again, and the parallel light is converged by the lens 5 to be fed back to the semiconductor laser 1, and a light emitted from the second facets is converged by the lens 7 to be output to an optical fiber 4.

Abstract: There is provided a wavelength tunable light source 10 in which one end surface 1a of a semiconductor laser 1 is applied anti-reflection film, a lens 6 collimates a light beam emitted from the one end surface 1a of the semiconductor laser 1 onto which the anti-reflection film is applied, and a wavelength selection portion constituted by a combination of a diffraction grating 2 and a mirror 3 selects a light beam having a desired wavelength to return the selected light to the semiconductor laser 1 to make laser oscillation. A center of rotation of the mirror 3 is provided in a position P0 where mode hopping can be suppressed when the wavelength is tuned and rotation of the mirror 3 is driven by a direct drive system by using a motor 4 having a rotation shaft 4a in the center of rotation of the mirror 3.

Abstract: A wavelength monitor capable of highly accurately and highly stably detecting a wavelength variation of a tunable laser source, and a motor control device for easily and highly precisely driving a motor which is wavelength varying means, by using the wavelength monitor.

Abstract: It is to provide a crosstalk improvement module capable of achieving high stability of the optical output at ease, by improving the crosstalk in the final stage with the crosstalk values deteriorated, in the optical power meter and the light source of the polarization maintaining fiber (PMF) output. The crosstalk improvement module intervening between a first polarization maintaining fiber and a second polarization maintaining fiber, comprises a first lens for making an output light from the first polarization maintaining fiber a parallel light, a polarizer for converting the parallel light into a linearly polarized light, a splitter for splitting an output light of the polarizer, a second lens for concentrating one of the lights split by the splitter and supplying the split light to the second polarization maintaining fiber, and a photoreceptor for receiving the other light split by the splitter.

Abstract: A wavelength-variable light source equipped with a semiconductor laser 1, one end of which is provided with an antireflection coating 1A, is equipped with a power correction filter 10 which permits transmission of the light output from the semiconductor laser 1, thereby rendering the characteristics of the output light substantially flat.

Abstract: An external resonator type wavelength variable light source comprises a semiconductor laser 5 formed on one end face with a antireflection coating 5a, a lens 6 for converting emitted light from the end face of the semiconductor laser 5 formed with the antireflection coating 5a into collimated light, a diffraction grating 7 for selecting a wavelength of the collimated light provided through the lens 6 and diffracting the light, and a mirror for reflecting the light diffracted through the diffraction grating 7 and feeding back the light again diffracted through the diffraction grating 7 into the semiconductor laser 5 through the lens 6. A V-groove grating mirror 8 having reflecting faces with an arrangement like a grating, of a plurality of V grooves 2 each shaped like V at right angles in cross section in a base material 1 with a reflection coating 3 formed on the surface of each V groove is used as the mirror.

Abstract: An external cavity laser type light source including a light emitting element, a wavelength selection element for selecting a wavelength of light emitted from the light emitting element and for returning light to the light emitting element, and an optical branch element arranged between the light emitting element and the wavelength selection element. In the external cavity laser type light source, selected light sent from the wavelength selection element is branched by the optical branch element, and one branched component is taken out as output light.

Abstract: In an optical interferometer, incident light 1 is divided into reflected light and transmitted light which travel along respective optical paths, which are orthogonal to each other. The reflected light is subjected to total reflection by means of a first reflector 3, and the transmitted light is subjected to total reflection by means of a second reflector 4. The light reflected by the first reflector 3 and the light reflected by the second reflector 4 are again merged by means of the beam splitter 2 into a single ray, and the thus-merged ray falls on a photodetector 5. The optical interferometer is equipped with a third reflector 6 which reflects the incident light 1 at right angles so as to fall on the beam splitter 2, and a fourth reflector 7 which reflects the light, having been transmitted through the beam splitter 2, at right angles so as to fall on the second reflector 4.

Abstract: There is provided a tunable filter with a wavelength monitor, that comprises a wavelength selector 3, a separator for separating a part of a transmitted light beam or a reflected light beam when a wavelength is swept by the wavelength selector, and a monitor 6 for monitoring a part of the separated light beam.

Abstract: The improved polarization analyzing apparatus comprises optical dividing member 2 which divides input light launched from an optical input section and an optical output section which supplies a polarization analyzer 1 with part of the light divided by the dividing member and which outputs the remaining light to the outside of the apparatus. A polarization controller 6 is provided in front of the optical dividing element and controlled in accordance with the polarization information from the polarization analyzer so as to retain a desired state of polarization.

Abstract: A tunable filter includes a polarizer, a polarization rotator, a diffraction grating and a diffraction grating adjustor. The polarizer polarizes a light beam and splits the light beam into first and second light beams. The polarization rotator rotates a plane of polarization of the first light beam at 90° to generate a rotated light beam. The diffraction grating receives the rotated light beam and the second light beam. The diffraction grating adjustor adjusts the diffraction grating to change incident angles of the rotated light beam and second light beam.

Abstract: A wavelength measuring apparatus capable of obtaining two signals by a single etalon, and which is physically stable and has high resolution so that direction to which wavelength varies can be recognized in wideband is provided. A Fabry-Perot etalon (etalon) is serves as a wavelength discriminating section of a wavelength measuring apparatus. A beam from an optical fiber passes through a lens generating a collimated beam. An optical branching section splits the collimated beam into two beams and inputs the two beams to the etalon. An optical axis of one split collimated beam is tilted with regard to an optical axis of another one such that each period of amplitude of the split collimated beams relatively shifts in &pgr;/2 phase difference. Each first and second photo detectors receives each split collimated beam which has transmitted the etalon, and detects a signal depending on the wavelength.

Abstract: A Fabry-Perot etalon comprises two faces having a reflecting film. A beam is transmitted through the Fabry-Perot etalon and split into two. One face is inclined to the other so that each of the two beams will relatively shift in a phase difference of &pgr;/2. The Fabry-Perot etalon is used as a wavelength discrimination unit. The beam transmitted through the Fabry-Perot etalon is branched off by a knife-edged mirror and reflected therein. The branched beams are received by first and second PDs, respectively, and signals which depend on wavelength are detected.