Abstract: An optical component has first and second planar lightwave circuits. The first and second planar lightwave circuits are aligned and jointed such that the position of an i-th optical waveguide (where i is an integer greater than or equal to 1 and less than or equal to n) of the first planar lightwave circuit and that of an i-th optical waveguide of the second planar lightwave circuit are matched on a joint interface. An angle formed by the i-th optical waveguide of the first planar lightwave circuit and a normal of the interface is configured to vary in accordance with a value of i within a range satisfying the Snell's law.

Abstract: An object of the present invention is to provide a temperature-independent optical frequency shifter for generating sub-carriers with a miniaturizable configuration, as well as to provide an all-optical OFDM modulator using the same that is compact, has low temperature dependence, and is even compatible with different frequency grids. Provided is an optical frequency shifter and an optical modulator using the same, the optical frequency shifter comprises one input optical port, a 1-input, 2-output optical coupler optically connected thereto, two Mach-Zehnder modulation units individually optically connected to the two outputs thereof, a 2-input, 2-output optical coupler optically connected to the individual outputs thereof, and two output optical ports optically connected to the outputs thereof, wherein the two Mach-Zehnder modulation units are driven by periodic waveforms at the same frequency whose phases differ from each other by (2p+1) ?/2 (p: integer).

Abstract: Provided is a waveguide-type polarization beam splitter in which deterioration of a polarization extinction ratio due to temperature change and wavelength change is suppressed. A groove is formed to extend across a pair of optical waveguide arms and two quarter wave plates are provided in the groove to extend respectively across the arms. Polarization axes of the quarter wave plates are orthogonal to each other. A first optical coupler which gives a phase difference of 0° or 180° between coupled or split light beams and a second optical coupler which gives a phase difference of 90° or ?90° between coupled or split light beams are used in combination.

Abstract: Provided is a waveguide-type polarization beam splitter in which deterioration of a polarization extinction ratio due to temperature change and wavelength change is suppressed. The waveguide-type polarization beam splitter includes: input optical waveguides; a first multimode interference optical coupler; a pair of optical waveguide arms; a second multimode interference optical coupler; and output optical waveguides. A quarter wavelength delay is provided in one of the pair of optical waveguide arms, a groove is formed to extend across both of the pair of optical waveguide arms, and two quarter wave plates are provided in the groove to extend respectively across the arms. Polarization axes of the respective quarter wave plates are orthogonal to each other.

Abstract: A planar lightwave circuit is provided which can be easily fabricated by an existing planar-lightwave-circuit fabrication process, which can lower the propagation loss of signal light and which can convert inputted signal light so as to derive desired signal light. A planar lightwave circuit having a core and a clad which are formed on a substrate, has input optical waveguide(s) (111) which inputs signal light, mode coupling part (112) for coupling a fundamental mode of the inputted signal light to a higher-order mode and/or a radiation mode, or mode re-coupling part (113) for re-coupling the higher-order mode and/or the radiation mode to the fundamental mode, and output optical waveguide(s) (114) which outputs signal light. The mode coupling part or the mode re-coupling part is an optical waveguide which has core width and/or height varied continuously.

Abstract: A planar lightwave circuit is provided which can be easily fabricated by an existing planar-lightwave-circuit fabrication process, which can lower the propagation loss of signal light and which can convert inputted signal light so as to derive desired signal light. A planar lightwave circuit having a core and a clad which are formed on a substrate, has input optical waveguide(s) (111) which inputs signal light, mode coupling part (112) for coupling a fundamental mode of the inputted signal light to a higher-order mode and/or a radiation mode, or mode re-coupling part (113) for re-coupling the higher-order mode and/or the radiation mode to the fundamental mode, and output optical waveguide(s) (114) which outputs signal light. The mode coupling part or the mode re-coupling part is an optical waveguide which has core width and/or height varied continuously.

Abstract: An arrayed waveguide grating optical multiplexer/demultiplexer according to the present invention including an input channel waveguide, an input slab waveguide, an arrayed waveguide, a polarization dependence eliminating means, an output slab waveguide, a temperature compensating means, and an output channel waveguide is characterized in that the temperature compensating means compensates for the temperature dependence of the optical path lengths in the channel waveguides of the arrayed waveguide, and the polarization dependence eliminating means eliminates the temperature dependence and the polarization dependence of the arrayed waveguide grating optical multiplexer/demultiplexer at the same time.

Abstract: A planar lightwave circuit is provided which can be easily fabricated by an existing planar-lightwave-circuit fabrication process, which can lower the propagation loss of signal light and which can convert inputted signal light so as to derive desired signal light. A planar lightwave circuit having a core and a clad which are formed on a substrate, has input optical waveguide(s) (111) which inputs signal light, mode coupling part (112) for coupling a fundamental mode of the inputted signal light to a higher-order mode and/or a radiation mode, or mode re-coupling part (113) for re-coupling the higher-order mode and/or the radiation mode to the fundamental mode, and output optical waveguide(s) (114) which outputs signal light. The mode coupling part or the mode re-coupling part is an optical waveguide which has core width and/or height varied continuously.

Abstract: In an optical component configured to fix to a mount an optical device chip in which a plurality of waveguide type optical devices having different thermal expansion coefficients are butt-jointed, deterioration in reliability due to thermal stress is suppressed. The optical component (300) comprises an optical device chip (310) including an LN waveguide (311), a first PLC waveguide (312) connected to an end of the LN waveguide (311), a second PLC waveguide (313) connected to the other end of the LN waveguide (311), and a fiber alignment member (314) connected to the first PLC waveguide (312), a mount (320) on which the optical device chip (310) is mounted, and optical fibers (330) aligned to the fiber alignment member (314).

Abstract: A Mach-Zehnder interferometer circuit (700) is provided with two couplers (722, 724) and two arm waveguides (706, 708) connecting the couplers with each other, each fabricated on a substrate, in which a polarization rotation device (732) is disposed in a groove dividing each of the two arm waveguides into two, the polarization rotation device (732) for converting vertically polarized light into horizontally polarized light, and birefringence is adjusted by performing laser irradiation or the like partially into at least one of the two arm waveguides such that a difference between birefringence values divided by an optical wavelength to be used is within a range of 2 m-0.2 to 2 m+0.2 (m is an integer including zero), the birefringence values being those integrated linearly along the respective two arm waveguides in an optical signal travelling direction.

Abstract: A planar lightwave circuit is provided which can be easily fabricated by an existing planar-lightwave-circuit fabrication process, which can lower the propagation loss of signal light and which can convert inputted signal light so as to derive desired signal light. A planar lightwave circuit having a core and a clad which are formed on a substrate, has input optical waveguide(s) (111) which inputs signal light, mode coupling part (112) for coupling a fundamental mode of the inputted signal light to a higher-order mode and/or a radiation mode, or mode re-coupling part (113) for re-coupling the higher-order mode and/or the radiation mode to the fundamental mode, and output optical waveguide(s) (114) which outputs signal light. The mode coupling part or the mode re-coupling part is an optical waveguide which has core width and/or height varied continuously.

Abstract: A planar lightwave circuit is provided which can be easily fabricated by an existing planar-lightwave-circuit fabrication process, which can lower the propagation loss of signal light and which can convert inputted signal light so as to derive desired signal light. A planar lightwave circuit having a core and a clad which are formed on a substrate, has input optical waveguide(s) (111) which inputs signal light, mode coupling part (112) for coupling a fundamental mode of the inputted signal light to a higher-order mode and/or a radiation mode, or mode re-coupling part (113) for re-coupling the higher-order mode and/or the radiation mode to the fundamental mode, and output optical waveguide(s) (114) which outputs signal light. The mode coupling part or the mode re-coupling part is an optical waveguide which has core width and/or height varied continuously.

Abstract: A Mach-Zehnder interferometer circuit (700) is provided with two couplers (722, 724) and two arm waveguides (706, 708) connecting the couplers with each other, each fabricated on a substrate, in which a polarization rotation device (732) is disposed in a groove dividing each of the two arm waveguides into two, the polarization rotation device (732) for converting vertically polarized light into horizontally polarized light, and birefringence is adjusted by performing laser irradiation or the like partially into at least one of the two arm waveguides such that a difference between birefringence values divided by an optical wavelength to be used is within a range of 2m?0.2 to 2m+0.2 (m is an integer including zero), the birefringence values being those integrated linearly along the respective two arm waveguides in an optical signal travelling direction.

Abstract: An arrayed waveguide grating optical multiplexer/demultiplexer according to the present invention including an input channel waveguide, an input slab waveguide, an arrayed waveguide, a polarization dependence eliminating means, an output slab waveguide, a temperature compensating means, and an output channel waveguide is characterized in that the temperature compensating means compensates for the temperature dependence of the optical path lengths in the channel waveguides of the arrayed waveguide, and the polarization dependence eliminating means eliminates the temperature dependence and the polarization dependence of the arrayed waveguide grating optical multiplexer/demultiplexer at the same time.

Abstract: A planar lightwave circuit is provided which can be easily fabricated by an existing planar-lightwave-circuit fabrication process, which can lower the propagation loss of signal light and which can convert inputted signal light so as to derive desired signal light. A planar lightwave circuit having a core and a clad which are formed on a substrate, has input optical waveguide(s) (111) which inputs signal light, mode coupling part (112) for coupling a fundamental mode of the inputted signal light to a higher-order mode and/or a radiation mode, or mode re-coupling part (113) for re-coupling the higher-order mode and/or the radiation mode to the fundamental mode, and output optical waveguide(s) (114) which outputs signal light. The mode coupling part or the mode re-coupling part is an optical waveguide which has core width and/or height varied continuously.

Abstract: A planar lightwave circuit is provided which can be easily fabricated by an existing planar-lightwave-circuit fabrication process, which can lower the propagation loss of signal light and which can convert inputted signal light so as to derive desired signal light. A planar lightwave circuit having a core and a clad which are formed on a substrate, has input optical waveguide(s) (111) which inputs signal light, mode coupling part (112) for coupling a fundamental mode of the inputted signal light to a higher-order mode and/or a radiation mode, or mode re-coupling part (113) for re-coupling the higher-order mode and/or the radiation mode to the fundamental mode, and output optical waveguide(s) (114) which outputs signal light. The mode coupling part or the mode re-coupling part is an optical waveguide which has core width and/or height varied continuously.

Abstract: The present invention provides an optical functional circuit where a holographic wave propagation medium is applied and a circuit property is excellent such as small transmission loss and crosstalk. The optical functional circuit where a plurality of circuit elements are formed on a substrate includes the wave propagation medium for converting an optical path of a leakage light so that the leakage light that is not emitted from a predetermined output port of the circuit element is not coupled to a different circuit element. This wave propagation medium is constituted by an optical waveguide that is provided with a clad layer formed on the substrate and a core embedded in the clad layer, and a part of the optical waveguide is formed in accordance with a refractive index distribution which is multiple scattered.

Abstract: A planar lightwave circuit is provided which can be easily fabricated by an existing planar-lightwave-circuit fabrication process, which can lower the propagation loss of signal light and which can convert inputted signal light so as to derive desired signal light. A planar lightwave circuit having a core and a clad which are formed on a substrate, has input optical waveguide(s) (111) which inputs signal light, mode coupling part (112) for coupling a fundamental mode of the inputted signal light to a higher-order mode and/or a radiation mode, or mode re-coupling part (113) for re-coupling the higher-order mode and/or the radiation mode to the fundamental mode, and output optical waveguide(s) (114) which outputs signal light. The mode coupling part or the mode re-coupling part is an optical waveguide which has core width and/or height varied continuously.

Abstract: The present invention provides an optical functional circuit where a holographic wave propagation medium is applied and a circuit property is excellent such as small transmission loss and crosstalk. The optical functional circuit where a plurality of circuit elements are formed on a substrate includes the wave propagation medium for converting an optical path of a leakage light so that the leakage light that is not emitted from a predetermined output port of the circuit element is not coupled to a different circuit element. This wave propagation medium is constituted by an optical waveguide that is provided with a clad layer formed on the substrate and a core embedded in the clad layer, and a part of the optical waveguide is formed in accordance with a refractive index distribution which is multiple scattered.

Abstract: By reducing the number of PD arrays, and by simplifying the configuration of an optical power monitor in a WDM system, a miniaturized, cost reduced optical signal monitoring apparatus, optical system or optical signal monitoring method is provided. An optical power monitor 1 has an optical switch 30 having four input ports 31, a DMUX 2 having 48 output ports, and six CSP type PD array modules 50 each including an 8-channel PD array. The output port 32 of the optical switch 30 having four switchable input ports 31 is optically connected to the input port 21 of the AWG 20. The 48 output ports 22 of the AWG 20 are each optically connected to photosensitive surfaces 53 of the individual PDs included in the CSP type PD array modules 50. The CSP type PD array modules 50 are mounted on the end face of the AWG 20.