Abstract: Disclosed is an optical delay element that makes use of a line-defect waveguide of a photonic crystal, in which long optical delay time and small group speed dispersion are rendered compatible with each other and in which waveform distortion that might otherwise be produced in processing an ultra-high speed signal is eliminated. Two line-defect waveguides 5 and 11, having different pillar diameters and group velocity dispersions of opposite signs, are interconnected by a line-defect waveguide 8, the pillar diameters of which are gradually varied from one 5 of the line-defect waveguides to the other line-defect waveguide 11, such as to compensate for group speed dispersion as well as to maintain an optical delay effect.

Abstract: There is provided an optical control device including a plurality of line-defect waveguides provided in a photonic crystal; each line-defect waveguide including a multiplicity of dielectric pillars with a finite height arranged at lattice points of a two-dimensional Bravais lattice. The optical control device comprises: a first line-defect waveguide; a second line-defect waveguide provided with the dielectric pillars having a thickness different from that of the dielectric pillars of the first line-defect waveguide; and a third line-defect waveguide arranged between the first and second line-defect waveguides and provided with the dielectric pillars whose thicknesses are gradually varied from those of the dielectric pillars of the first line-defect waveguide to those of the dielectric pillars of the second line-defect waveguide along a wave guiding direction.

Abstract: An optical converter comprises: a first waveguide, a second waveguide, and a tapered waveguide arranged between both the waveguides, wherein heights of a core of the first waveguide and a core of the second waveguide are different; both ends in a direction of wave guiding of a core of the tapered waveguide are respectively connected to the core of the first waveguide and the core of the second waveguide; cross-sectional shapes and refractive indexes of cores of two waveguides that are connected change continuously or in a stepwise manner at each connection part; and a cross-sectional shape and refractive index of the core of the tapered waveguide change continuously or in a stepwise manner along a direction of wave guiding.

Abstract: An optical circuit comprises: a first waveguide; a second waveguide: and a third waveguide that converts mode field and direction of polarization of light of said first waveguide at the same time to perform wave guiding to said second waveguide: wherein large aspect ratio directions of corresponding ends of a core of said first waveguide and a core of said second waveguide differ from each other.

Abstract: A wavelength filter includes a first waveguide with a transmission band of a predetermined basic mode and a second waveguide, arranged in at least one location of the first waveguide, with a transmission band whose cutoff frequency corresponds to a finite value included in the transmission band of the basic mode. A pair of optical couplers constituting a Mach-Zehnder interferometer is connected to the opposite ends of a filter unit including the first waveguide and the second waveguide. When a plurality of wavelength filters is cascaded, the wavelength filters can be each varied in terms of the cutoff frequency of the second waveguide.

Abstract: An optical switch is constituted of a wavelength filter and a control device. The wavelength filter includes a first waveguide exhibiting a transmission band of a predetermined basic mode and a second waveguide, arranged in at least one location of the first waveguide, exhibiting a transmission band with a cutoff frequency corresponding to a finite value included in the transmission band of the basic mode. A pair of optical couplers constituting a Mach-Zehnder interferometer is connected to opposite ends of a filter unit including the first waveguide and the second waveguide. When a plurality of wavelength filters is cascaded, these wavelength filters differ from each other in terms of the cutoff frequency of the second waveguide. The control device changes the cutoff frequency of the second waveguide within the transmission band of the first waveguide, thus adjusting the filtering band of the wavelength filter.

Abstract: A coupling structure of waveguide including a line defect (LD) waveguide portion having an LD waveguide, an electromagnetic field distribution matching portion (EFDMP) connected between the LD waveguide portion and a first tapered portion, the first tapered portion connected with the EFDMP, and a thin line waveguide portion connected with the first tapered portion and having a thin line waveguide. The EFDMP has a matching portion LD as the LD of a columnar photonic crystal, and the matching portion LD is connected with the LD waveguide. The first tapered portion consists of a first thin wire core, and the first LD of a columnar photonic crystal arranged along at least one side of first thin line core. At least one of the first thin line core and the first LD is connected with the matching portion line defect. The thin line waveguide is connected with the first thin line core.

Abstract: The object is to provide an optical switch capable of efficient operation and a manufacturing method thereof. The optical switch according to the present invention is a Mach-Zehnder interferometer type optical switch composed of a line defect waveguide of a photonic crystal. Further, the optical switch according to the present invention includes two directional couplers 20 and 23, and two paths of waveguides 30 and 32 therebetween. Furthermore, between the two paths, group velocity of guided light differs in the first path waveguide 20 and the second path waveguide 32.

Abstract: In an exemplary embodiment, an optical waveguide (10) includes a first dielectric medium (11). In the first dielectric medium (11), line-defect rods (12) are arranged in one row and non-line-defect rods (13) are arranged along the row of line-defect rods (12) and on both sides of the row of the line-defect rods (12). The line-defect rods (12) and non-line-defect rods (13) form a two-dimensional square lattice. Of the rows of non-line-defect rods (13) arranged on the two sides of the row of line-defect rods (12), the number of rows of non-line-defect rods (13) on at least one side is at least one and no greater than five.

Abstract: Provided is an optical switch that can be operated efficiently and a method of manufacturing the same. The optical switch according to the present invention is an optical switch of Mach-Zehnder interferometer type formed by a line-defect waveguide of a photonic crystal. Further, the optical switch includes a branch 7, a directional coupler 15, and waveguides 90 and 91 of two paths between them. The waveguide 90 of a first path and the waveguide 91 of a second path among the waveguides 90 and 91 of the two paths have different group velocities of guided light.

Abstract: A waveguide stub is connected to a pillar-type square-lattice photonic crystal waveguide. Within the waveguide stub, the diameter of a defect is made larger than that of the original photonic crystal waveguide thereby reducing the group velocity of a guided light. The original waveguide and the waveguide stub are smoothly connected via a taper waveguide. Because of low group velocity of light in the waveguide stub, free spectral range (FSR) decreases thereby allowing the size of the waveguide stub to be reduced.

Abstract: A coupling structure of waveguide including a line defect (LD) waveguide portion having an LD waveguide, an electromagnetic field distribution matching portion (EFDMP) connected between the LD waveguide portion and a first tapered portion, the first tapered portion connected with the EFDMP, and a thin line waveguide portion connected with the first tapered portion and having a thin line waveguide. The EFDMP has a matching portion LD as the LD of a columnar photonic crystal, and the matching portion LD is connected with the LD waveguide. The first tapered portion consists of a first thin wire core, and the first LD of a columnar photonic crystal arranged along at least one side of first thin line core. At least one of the first thin line core and the first LD is connected with the matching portion line defect. The thin line waveguide is connected with the first thin line core.

Abstract: An optical converter comprises: a first waveguide, a second waveguide, and a tapered waveguide arranged between both the waveguides, wherein heights of a core of the first waveguide and a core of the second waveguide are different; both ends in a direction of wave guiding of a core of the tapered waveguide are respectively connected to the core of the first waveguide and the core of the second waveguide; cross-sectional shapes and refractive indexes of cores of two waveguides that are connected change continuously or in a stepwise manner at each connection part; and a cross-sectional shape and refractive index of the core of the tapered waveguide change continuously or in a stepwise manner along a direction of wave guiding.

Abstract: There is provided an optical control device including a plurality of line-defect waveguides provided in a photonic crystal; each line-defect waveguide including a multiplicity of dielectric pillars with a finite height arranged at lattice points of a two-dimensional Bravais lattice. The optical control device comprises: a first line-defect waveguide; a second line-defect waveguide provided with the dielectric pillars having a thickness different from that of the dielectric pillars of the first line-defect waveguide; and a third line-defect waveguide arranged between the first and second line-defect waveguides and provided with the dielectric pillars whose thicknesses are gradually varied from those of the dielectric pillars of the first line-defect waveguide to those of the dielectric pillars of the second line-defect waveguide along a wave guiding direction.

Abstract: An optical circuit comprises a first waveguide; a second waveguide; and a third waveguide that converts mode field and direction of polarization of light of said first waveguide at the same time to perform wave guiding to said second waveguide; wherein large aspect ratio directions of corresponding ends of a core of said first waveguide and a core of said second waveguide differ from each other.

Abstract: The present invention provides an optical switch having a photonic crystal structure. An optical switch of the invention has a slab optical waveguide structure whose core (35) has a two-dimensional photonic crystal structure where two or more media (33, 34) with different refractive indices are alternately and regularly arranged in a two-dimensional manner. The photonic crystal structure comprises: a line-defect waveguide; and means for altering the refractive index of the line-defect waveguide.

Abstract: Disclose is a photonic crystal structure comprises atomic dielectric pillars having a refractive index distribution and a structure which are both mirror-symmetrical in a thicknesswise direction of the photonic crystal. The atomic pillars are arrayed in a two-dimensional lattice pattern to form a dielectric pillar lattice. The dielectric pillar lattice is disposed within a surrounding dielectric having a uniform or substantially uniform refractive index distribution. An organic resin which serves as part of surrounding dielectric is disposed in an asymmetrical position in a thicknesswise direction of the photonic crystal.

Abstract: A microchip includes a clad layer having a channel through which a sample flows, and an optical waveguide formed within the clad layer and having a higher refractive index than the clad layer. The optical waveguide is formed to act on the channel optically. Thus, the sample flowing in the channel can be analyzed with high accuracy even in the microchip having a fine structure.

Abstract: Disclose is a photonic crystal structure comprises atomic dielectric pillars having a refractive index distribution and a structure which are both mirror-symmetrical in a thicknesswise direction of the photonic crystal. The atomic pillars are arrayed in a two-dimensional lattice pattern to form a dielectric pillar lattice. The dielectric pillar lattice is disposed within a surrounding dielectric having a uniform or substantially uniform refractive index distribution. An organic resin which serves as part of surrounding dielectric is disposed in an asymmetrical position in a thicknesswise direction of the photonic crystal.

Abstract: The present invention provides an optical switch having a photonic crystal structure. An optical switch of the invention has a slab optical waveguide structure whose core (35) has a two-dimensional photonic crystal structure where two or more media (33, 34) with different refractive indices are alternately and regularly arranged in a two-dimensional manner. The photonic crystal structure comprises: a line-defect waveguide; and means for altering the refractive index of the line-defect waveguide.