Abstract: Provided is an optical module comprising a substrate, a holder, and a spacer. An optical waveguide is formed in/on the substrate and end parts thereof are protruding from one surface of the substrate. The holder holds an optical fiber and exposes one end part of the optical fiber in such a manner that the one end part of the optical fiber can be optically connected to the end parts of the optical waveguide at a side of one surface of the holder. The spacer is held the one surface of the substrate and the one surface of the holder.

Abstract: Provided is an optical module comprising a substrate, a holder, and a spacer. An optical waveguide is formed in/on the substrate and end parts thereof are protruding from one surface of the substrate. The holder holds an optical fiber and exposes one end part of the optical fiber in such a manner that the one end part of the optical fiber can be optically connected to the end parts of the optical waveguide at a side of one surface of the holder. The spacer is held the one surface of the substrate and the one surface of the holder.

Abstract: An electro-optical modulator includes a substrate 201; an optical waveguide formed of a silicon-containing i-type amorphous semiconductor 204 on the substrate; and a silicon-containing p-type semiconductor layer 203 and a silicon-containing n-type semiconductor layer 205 arranged apart from each other with the silicon-containing optical waveguide formed of an i-type amorphous semiconductor 204 interposed therebetween and constituting optical waveguides together with the silicon-containing optical waveguide formed of an i-type amorphous semiconductor. The silicon-containing p-type semiconductor layer 203 and/or silicon-containing n-type semiconductor layer 205 area crystalline semiconductor layer.

Abstract: An optical semiconductor device in which a first optical waveguide 407 comprising a silicon-containing amorphous semiconductor layer and a second optical waveguide 409 containing a silicon-containing i-type semiconductor layer as a constituent element are disposed in different layers in a range in which optical interaction can occur. An electro-optical modulator 409 having a pin junction structure comprising a p-type semiconductor layer 403, an i-type semiconductor layer 404, and an n-type semiconductor layer 405 is provided to at least a portion of the second optical waveguide 409, and the index of refraction of the second optical waveguide is varied by the electro-optical modulator, whereby light waves propagated through the first optical waveguide are modulated.

Abstract: An optical semiconductor device in which a first optical waveguide 407 comprising a silicon-containing amorphous semiconductor layer and a second optical waveguide 409 containing a silicon-containing i-type semiconductor layer as a constituent element are disposed in different layers in a range in which optical interaction can occur. An electro-optical modulator 409 having a pin junction structure comprising a p-type semiconductor layer 403, an i-type semiconductor layer 404, and an n-type semiconductor layer 405 is provided to at least a portion of the second optical waveguide 409, and the index of refraction of the second optical waveguide is varied by the electro-optical modulator, whereby light waves propagated through the first optical waveguide are modulated.

Abstract: An object of the present invention is to provide an electro-optical modulator that allows high-speed carrier injection into a silicon-containing i-type amorphous semiconductor, particularly a-Si:H, and has little optical loss. An electro-optical modulator comprises: a substrate 201; an optical waveguide comprising a silicon-containing i-type amorphous semiconductor 204 formed on the substrate; and a silicon-containing p-type semiconductor layer 203 and a silicon-containing n-type semiconductor layer 205 arranged apart from each other with the silicon-containing optical waveguide comprising an i-type amorphous semiconductor 204 interposed therebetween and constituting optical waveguides together with the silicon-containing optical waveguide comprising an i-type amorphous semiconductor. The silicon-containing p-type semiconductor layer 203 and/or silicon-containing n-type semiconductor layer 205 are a crystalline semiconductor layer.

Abstract: A method is provided for processing a silicon-based wire optical waveguide, by which an optical transmission loss of the silicon-based wire optical waveguide due to ion irradiation with high energy is suppressed, and an end portion of the silicon-based wire optical waveguide that is three-dimensionally curved in a self-aligning manner is obtained. According to the method a protective film is selectively formed on the silicon-based wire optical waveguide exclusive of the end portion of the silicon-based wire optical waveguide; and ions are implanted to the silicon-based wire optical waveguide in a particular direction, so as to curve the end portion of the silicon-based wire optical waveguide to the particular direction in a self-alignment manner.

Abstract: An interlayer light wave coupling device includes a substrate; a first core disposed on the substrate and having a first acute structure; a third core spatially set apart from the first core and having a second acute structure; and a second core disposed between the first core and the third core and having a smaller index of refraction than the first core and the third core. The acute structures of the first core and the third core are disposed so as to have no overlap as viewed from above.

Abstract: An interlayer light wave coupling device includes a substrate; a first core disposed on the substrate and having a first acute structure; a third core spatially set apart from the first core and having a second acute structure; and a second core disposed between the first core and the third core and having a smaller index of refraction than the first core and the third core. The acute structures of the first core and the third core are disposed so as to have no overlap as viewed from above.

Abstract: A method is provided for processing a silicon-based wire optical waveguide, by which an optical transmission loss of the silicon-based wire optical waveguide due to ion irradiation with high energy is suppressed, and an end portion of the silicon-based wire optical waveguide that is three-dimensionally curved in a self-aligning manner is obtained. According to the method a protective film is selectively formed on the silicon-based wire optical waveguide exclusive of the end portion of the silicon-based wire optical waveguide; and ions are implanted to the silicon-based wire optical waveguide in a particular direction, so as to curve the end portion of the silicon-based wire optical waveguide to the particular direction in a self-alignment manner.

Abstract: A semiconductor pointed structure formed at an end portion of the core structure of a semiconductor photonic wire waveguide has a sloped side wall on at least one of the sides that constitute the pointed structure. The semiconductor pointed structure decreases in width and thickness towards the distal end. A method for fabrication of the structure is also disclosed.

Abstract: In the present invention, a nonionic surfactant is noticed for a function of dispersing a carbon nanotube, and it is found that a mixture solution of an amide-based organic solvent and a polyvinylpyrrolidone (PVP) or of the amide-based organic solvent, the nonionic surfactant, and the polyvinylpyrrolidone (PVP) has an excellent function as a dispersant for the carbon nanotube. Ultrasonication is required for dispersing a carbon nanotube in the dispersant. The ultrasonication may be carried out in the step of dispersing the carbon nanotube in the nonionic surfactant and/or the amide-based polar organic solvent, and then the polyvinylpyrrolidone (PVP) may be mixed with the resultant dispersion. Alternatively, a mixture solution of the nonionic surfactant and/or the amide-based polar organic solvent, and the polyvinylpyrrolidone (PVP) is prepared, and then the ultrasonication may be carried out in the step of dispersing the carbon nanotube therein.

Abstract: A carbon nanotube-dispersed polyimide saturable absorber excellent in an optical quality, obtainable by mixing a carbon nanotube dispersion liquid comprising a carbon nanotube, an amide-based polar organic solvent, and a nonionic surfactant and/or a polyvinylpyrrolidone (PVP) with a mixture solution of a solvent soluble polyimide and an organic solvent. A method for producing the same, comprising the steps of dispersing a single-walled carbon nanotube in a mixture solution of an amide-based polar organic solvent and a nonionic surfactant under intensive stirring, mixing the resultant dispersion liquid with a polyimide mixed organic solvent, and removing the solvent.

Abstract: In the present invention, a nonionic surfactant is noticed for a function of dispersing a carbon nanotube, and it is found that a mixture solution of an amide-based organic solvent and a polyvinylpyrrolidone (PVP) or of the amide-based organic solvent, the nonionic surfactant, and the polyvinylpyrrolidone (PVP) has an excellent function as a dispersant for the carbon nanotube. Ultrasonication is required for dispersing a carbon nanotube in the dispersant. The ultrasonication maybe carried out in the step of dispersing the carbon nanotube in the nonionic surfactant and/or the amide-based polar organic solvent, and then the polyvinylpyrrolidone (PVP) may be mixed with the resultant dispersion. Alternatively, a mixture solution of the nonionic surfactant and/or the amide-based polar organic solvent, and the polyvinylpyrrolidone (PVP) is prepared, and then the ultrasonication may be carried out in the step of dispersing the carbon nanotube therein.

Abstract: Non-linear optical characteristics of a carbon nanotube are applied to an optical communication field. An optical transmission medium (12) obtained by incorporating a carbon nanotube having optically non-linear characteristics into a non-linear light transmitting medium is assembled between typical optical transmission medium (14a, 14b) and is used by being combined with an optical circulator (16), whereby the resultant product is used as an optical fuse (breaker) that transmits a normal signal light A but blocks the transmission of an abnormal-intensity light inadvertently produced.

Abstract: An optical element according to the present invention has a thin film, in which single-wall carbon nanotubes are laminated, and utilizes a saturable absorption function of the single-wall carbon nanotubes. Further, in a method for producing the optical element according to the present invention, the thin film is formed by spraying, to a body to be coated, a dispersion liquid prepared by dispersing the single-wall carbon nanotubes in a dispersion medium. Accordingly, a nonlinear optical element, which can operate in an optical communication wavelength region and which is extremely inexpensive and efficient, and a method for producing the optical element can be provided.

Abstract: An increase in the span of the transmission distance is aimed at by reducing unwanted ASE generated during optical communication. A carbon nanotube is employed as a saturable absorber 15 and this saturable absorber constitutes a noise reduction apparatus that has the function of cutting off or reducing transmission of unwanted ASE or the like which is of weak signal light intensity and of allowing transmission of signal light of strong light intensity. This noise reduction apparatus is arranged for example in the transmission path of signal light of a bidirectional excitation type EDFA, more precisely the apparatus is inserted in the latter stage of the EDF 40. In this way, carbon nanotubes having a saturable absorption function can be utilized in the field of optical communication.