Abstract: A method for adjusting a transmission wavelength of signal light transmitted through an optical waveguide device provided with one or more optical waveguides through which the signal light having a wavelength of 1520 nm to 1560 nm and blue light having a wavelength of 375 nm to 455 nm pass, a groove through which the waveguide passes, and resin filled in the groove, including a step of passing the signal light and the blue light through the same or mutually different one or more optical waveguides and of passing the signal light and the blue light through the same or mutually different resin, the latter step changing a refractive index of the resin by irradiating the resin with the blue light so as to change the transmission wavelength of the signal light transmitted through the resin in accordance with a change in the refractive index of the resin.

Abstract: Provided is an optical waveguide circuit in which the space between waveguides, a waveguide groove, or the space between fibers is filled with a resin where a wavelength shifts to positive (shifts backward) instead of a conventional resin where a wavelength shifts to negative (shifts forward), to return a refractive index having decreased by an instantaneous change to the original refractive index. In the filling resin with which the space between the waveguides, the waveguide groove, the space between the fibers, or the space between the fiber and the waveguide is filled, upon input of light, a refractive index of a portion through which the light passes instantaneously decreases, and then the refractive index gradually increases to compensate the initial decrease in the refractive index.

Abstract: An optical module includes a planar lightwave circuit optically connected to an optical fiber; a fiber block to which the optical fiber is fixed; and a glass layer that bonds and fixes the fiber block and the planar lightwave circuit. The glass layer is provided in a portion through which light passes between the optical fiber and the planar lightwave circuit in a gap between the connection end face of the fiber block and the connection end face of the planar lightwave circuit. The optical module further includes a thin tube. The thin tube may be provided to penetrate the fiber block. The thin tube can be provided so as to penetrate the planar lightwave circuit or a fixture plate mounted on the planar lightwave circuit.

Abstract: An optical module capable of suppressing deterioration of an adhesive layer and having a resistance to high-power light even when high-energy light propagates is configured by connecting an optical fiber to a PLC. The optical fiber is provided with an etching face at a recessed area where a cladding region on its side face is partially removed over a length L in a light propagation direction from an input/output end connected to the PLC, and the PLC is also provided with an etching face at a recessed area where a cladding layer is partially removed over the length L in the light propagation direction from an input/output end connected to the optical fiber. The adhesive layer made of a UV cured resin is interposed between the etching faces to bond and fix the etching faces to each other, and a core of the optical fiber and a core layer of the PLC form a directional coupler for linearly dispersing energy density.

Abstract: There is provided an optical waveguide chip. In the optical waveguide chip, an optical waveguide circuit includes a substrate, a lower clad layer laminated on the substrate, a core layer that is laminated on the lower clad layer and corresponds to a propagation path of an optical signal, and an upper clad layer laminated on the core layer; the upper and lower clad layers in a region that does not correspond to the propagation path of the optical signal are removed across to an edge of the chip; the region from which the upper and lower clad layers have been removed is filled with a light absorbing material; and a height of the filled light absorbing material is higher than a height of an uppermost surface of the upper clad layer.

Abstract: An end portion structure of a transmission line of the present invention is a structure in which a protective film with a thickness of 0.5 ?m to 3.0 ?m is formed on the end surface of the transmission line in place of an end cap formed in an end portion of a transmission line in the related art, and no adhesive is used in a portion through which light passes. The protective film on the end surface works to suppress a bulge of the core. The thickness of the protective film is significantly thinner than the end cap, and thus waveguides facing each other can be brought close to each other. It is possible to reduce the connection loss between two fibers or waveguides facing each other to be 0.5 dB or less. Since no adhesive is used, there is no loss increase caused by adhesive deterioration.

Abstract: To provide an optical connector that can prevent degradation of end faces of cores using a simple structure. The optical connector is adapted to connect single-mode optical fibers for visible light with a wavelength of less than or equal to 650 nm to ultraviolet light, specifically, connect the optical fibers by allowing ferrules having fixed thereto the respective optical fibers to be inserted into a sleeve and allowing the ferrules to butt against each other, in which a film of nitride, oxide, or fluoride is formed on an end face of each of the optical fibers and the ferrules.

Abstract: A dependency of a characteristic of an optical circuit on an optical signal intensity occurring due to input of a high intensity optical signal is reduced in a waveguide type optical interferometer circuit. The waveguide type optical interferometer circuit is a waveguide type optical interferometer circuit formed in one plane, and includes an input waveguide, an optical branching unit, an optical coupling unit, an output waveguide, and optical waveguides having different lengths from each other and being interposed between the optical branching unit and the optical coupling unit. A light intensity compensating region is formed on an optical path extending from the optical branching unit to the optical coupling unit, and the light intensity compensating region is formed by using a light intensity compensating material having a light intensity coefficient different from a light intensity coefficient of an optical distance relative to an incident light intensity in the optical path.

Abstract: Provided is an optical waveguide circuit in which the space between waveguides, a waveguide groove, or the space between fibers is filled with a resin where a wavelength shifts to positive (shifts backward) instead of a conventional resin where a wavelength shifts to negative (shifts forward), to return a refractive index having decreased by an instantaneous change to the original refractive index. In the filling resin with which the space between the waveguides, the waveguide groove, the space between the fibers, or the space between the fiber and the waveguide is filled, upon input of light, a refractive index of a portion through which the light passes instantaneously decreases, and then the refractive index gradually increases to compensate the initial decrease in the refractive index.

Abstract: A method for adjusting a transmission wavelength of signal light transmitted through an optical waveguide device provided with one or more optical waveguides through which the signal light having a wavelength of 1520 nm to 1560 nm and blue light having a wavelength of 375 nm to 455 nm pass, a groove through which the waveguide passes, and resin filled in the groove, including a step of passing the signal light and the blue light through the same or mutually different one or more optical waveguides and of passing the signal light and the blue light through the same or mutually different resin, the latter step changing a refractive index of the resin by irradiating the resin with the blue light so as to change the transmission wavelength of the signal light transmitted through the resin in accordance with a change in the refractive index of the resin.

Abstract: A dependency of a characteristic of an optical circuit on an optical signal intensity occurring due to input of a high intensity optical signal is reduced in a waveguide type optical interferometer circuit. The waveguide type optical interferometer circuit is a waveguide type optical interferometer circuit formed in one plane, and includes an input waveguide, an optical branching unit, an optical coupling unit, an output waveguide, and optical waveguides having different lengths from each other and being interposed between the optical branching unit and the optical coupling unit. A light intensity compensating region is formed on an optical path extending from the optical branching unit to the optical coupling unit, and the light intensity compensating region is formed by using a light intensity compensating material having a light intensity coefficient different from a light intensity coefficient of an optical distance relative to an incident light intensity in the optical path.

Abstract: A technique for electrically mounting a surface-normal optical device or material on a waveguide-type optical device while the characteristics of the mounted device are effectively used is disclosed. The waveguide-type optical device comprises a substrate on which optical waveguides or fibers are provided and a trench is formed; a pair of electrodes which is assigned to each optical waveguide or fiber and is formed from the surface of the substrate to wall surfaces of the trench; and a material or device which is filled or inserted into the trench, and which has an electro-optic effect, thermo-optic effect, light emitting function, light receiving function, or light modulating function. Another type of device comprises a thin and surface-normal active optical device driven by an applied voltage, which is substantially vertically inserted into the trench and is fixed in the trench; and a support member attached to the inserted device.

Abstract: Fabry-Perot etalon type tunable wavelength-selective filter comprises: a first layer including a transparent electrode and an optical mirror layer; a third layer including a transparent electrode and an optical mirror layer; and a second layer which is composed of a material with a refractive index variable with electric field, and sandwiched between the first layer and the third layer, wherein the material having a refractive index variable with electric field is composed by dispersing liquid crystal droplets equal to or less than 150 nm in diameter in a light transmissive characteristic medium such as a polymer or silica glass, and by adding plasticizer therein. In this structure, the optical mirror layer consists of a dielectric multilayer mirror with an optical reflectance of equal to or more than 95% for 1.

Abstract: A technique for electrically mounting a surface-normal optical device or material on a waveguide-type optical device while the characteristics of the mounted device are effectively used is disclosed. The waveguide-type optical device comprises a substrate on which optical waveguides or fibers are provided and a trench is formed; a pair of electrodes which is assigned to each optical waveguide or fiber and is formed from the surface of the substrate to wall surfaces of the trench; and a material or device which is filled or inserted into the trench, and which has an electro-optic effect, thermo-optic effect, light emitting function, light receiving function, or light modulating function. Another type of device comprises a thin and surface-normal active optical device driven by an applied voltage, which is substantially vertically inserted into the trench and is fixed in the trench; and a support member attached to the inserted device.

Abstract: The optical beam emitted from the transmitter array is input into the polarization beam splitter, and then turned by a right angle to input the opening portion of the neighboring board. Then, polarization of the optical beam is controlled by the polarization control array device provided on the opening portion to thereby rotate a plane of polarization by 90.degree., then the optical beam is turned by the polarization beam splitter by a right angle to input into the first light deflection control array device which then controls the propagation direction of the optical beam to input into the desired photodetector. On the other hand, the optical beam whose plane of polarization is not rotated by the polarization control array device by 90.degree. passes through the polarization beam splitter along the propagation direction to input into the opening portion of the neighboring board, and is then controlled similarly.

Abstract: A liquid crystal microprism array has a plurality of grooves formed on a surface of a transparent substrate, a plurality of spaces divided by ridges of the grooves, and a plurality of liquid crystal cells placed in the spaces.

Abstract: A tunable wavelength-selective filter includes a glass substrate, a transparent electrode layer, a highly reflective mirror, an alignment layer, a liquid crystal layer, another alignment layer, a transparent material layer whose refractivity index is substantially equal to that of the liquid crystal layer, another highly reflective mirror, another transparent electrode layer, and another glass substrate, which are stacked in this order. An etalon cavity of the filter includes two layers, the liquid crystal layer and the transparent material layer (such as a glass plate), which enables the cavity length to be increased without increasing absorption and scattering of the cavity. This makes it possible to narrow the FWHM, quicken the response time, and increase the transmittance of the filter. Applications for the filter include a double cavity structure tunable wavelength-selective filter of a wide tunable range, and a photodetector of a simple construction.