Abstract: A processing method for suppressing photodarkening in an Yb-doped optical fiber, comprising: a first step of preparing the Yb-doped optical fiber by doping a core with Yb, and irradiating at least one of a gamma ray, a X-ray, or an electron beam onto the Yb-doped optical fiber with an energy greater than a light to be transmitted through the optical fiber when a laser is being oscillated; a second step of measuring a loss spectrum of an infrared region of the optical fiber after the first step, and selecting an optical fiber with the loss in a specific wavelength falling within a predetermined range; and a third step of treating the optical fiber selected in the second step in an atmosphere containing hydrogen to obtain an Yb-doped optical fiber with suppressed photodarkening.

Abstract: A processing method for suppressing photodarkening in an Yb-doped optical fiber, comprising: a first step of preparing the Yb-doped optical fiber by doping a core with Yb, and irradiating at least one of a gamma ray, a X-ray, or an electron beam onto the Yb-doped optical fiber with an energy greater than a light to be transmitted through the optical fiber when a laser is being oscillated; a second step of measuring a loss spectrum of an infrared region of the optical fiber after the first step, and selecting an optical fiber with the loss in a specific wavelength falling within a predetermined range; and a third step of treating the optical fiber selected in the second step in an atmosphere containing hydrogen to obtain an Yb-doped optical fiber with suppressed photodarkening.

Abstract: A light source controlling circuit controls a light source outputting continuous light. The light source controlling circuit has a power supply circuit supplying an electric power to the light source, a light source monitoring circuit monitoring a state of the light source, and a control circuit outputting a first control signal to control the light source is controlled. The light source monitoring circuit outputs a second control signal to control the light source in correspondence to a state of the light source. A portable electronic apparatus has a light source outputting continuous light, an image pickup device, and the light source controlling circuit. The light source controlling circuit, for example, controls ON/OFF of the light source in accordance with a temperature of the light source detected by the light source monitoring circuit.

Abstract: A collimator lens having a low reflectivity and significantly improved durability against high-power light is provided so that optical parts using the collimator lens can be reduced in size and cost lowered. A plurality of optical fibers can be connected to the collimator lens to produce a variety of fiber collimators and optical parts based on the fiber collimator. The collimator lens is made essentially of quarts glass whose refractive index is graded radially so as to increase towards the optical axis and decrease gradually towards the outer periphery. The collimator lens and optical fibers are connected directly by fusion.

Abstract: An optical connector ferrule has an optical fiber containing hole reaching from the rear end surface near the end surface and a fine pore extending from the optical fiber accommodating hole to the end surface to be connected. A bare fiber of a polarization-maintaining optical fiber is inserted into the fine pore. Since the length of the fine pore is short, the influence of the uniformness of the adhesive in the fine pore is smaller, and therefore the stress distribution is maintained, resulting in stabilizing the polarization characteristics. A flange unit is attached to the ferrule after an optical fiber is inserted to the ferrule and fixed. Therefore the optical fiber is easily adjusted with respect to the housing in the circumferential direction around the axis, and optical fibers are connected by but joining with high accuracy.

Abstract: A light source controlling circuit controls a light source outputting continuous light. The light source controlling circuit has a power supply circuit supplying an electric power to the light source, a light source monitoring circuit monitoring a state of the light source, and a control circuit outputting a first control signal to control the light source is controlled. The light source monitoring circuit outputs a second control signal to control the light source in correspondence to a state of the light source. A portable electronic apparatus has a light source outputting continuous light, an image pickup device, and the light source controlling circuit. The light source controlling circuit, for example, controls ON/OFF of the light source in accordance with a temperature of the light source detected by the light source monitoring circuit.

Abstract: This two input two output type optical switch includes four one input two output type optical switches which are arranged to oppose one another, each of these one input two output type optical switches including a Y branch portion in which one optical waveguide is branched into two optical waveguides. And two refractive index adjustment means are provided in the vicinity of each Y branch portion. Switching over of the optical path is performed by half of the refractive index adjustment means functioning alternately. Moreover, a light output intensity variable attenuation function which attenuates by any desired amount the intensity of the light which is being outputted is implemented, at some input port and/or output port, by operating at least one of the refractive index adjustment means which is not currently being used for switching over of the optical path.

Abstract: The present invention relates a method for manufacturing an optical coupler/splitter. A Y-shaped waveguide core is formed by focusing a laser beam into a cladding layer that is formed from a glass material. At least one portion of this Y-shaped waveguide core other than the input port and the output ports is treated as a refractive index adjustment area. After the portions of the Y-shaped waveguide core other than the refractive index adjustment area have been formed by focusing a laser beam, signal light is inputted into the input port of the Y-shaped waveguide core and the signal light outputted from the output ports of the Y-shaped waveguide core are monitored. The refractive index of the refractive index adjustment area is determined based on the result of the monitoring and is adjusted by focusing a laser beam repeatedly.

Abstract: An optical connector ferrule has an optical fiber containing hole reaching from the rear end surface near the end surface and a fine pore extending from the optical fiber accommodating hole to the end surface to be connected. A bare fiber of a polarization-maintaining optical fiber is inserted into the fine pore. Since the length of the fine pore is short, the influence of the uniformness of the adhesive in the fine pore is smaller, and therefore the stress distribution is maintained, resulting in stabilizing the polarization characteristics. A flange unit is attached to the ferrule after an optical fiber is inserted to the ferrule and fixed. Therefore the optical fiber is easily adjusted with respect to the housing in the circumferential direction around the axis, and optical fibers are connected by but joining with high accuracy.

Abstract: When an optical waveguide is formed by focused femtosecond laser pulses in a pure silica glass to induce a refractive index increase region, a pulse width of femtosecond laser pulses are changed, a peak power of femtosecond laser pulses at the focal point is changed, or both the pulse width and the peak power are changed simultaneously. Under conditions where a pulse width of the femtosecond laser pulses is in a range of 210 to 420 fs and a peak power at the focal point is not greater than 8.7×1011 W/cm2, an optical waveguide having a mode field of 10 to 14 ?m such that an aspect ratio is 1 (one) can be obtained. By doing this, it is possible to control a mode field diameter of an optical waveguide and an aspect ratio of the mode field diameter.

Abstract: An optical switch operating on thermooptic effects has a branching section heater for heating a branching section of a core and a branched core heater for heating a branched core. The heaters are controlled separately so that the branching section and the branched core can be heated to respective temperatures so as to minimize insertion loss of inputted light and to prevent outputting light from a port not intended for light output.

Abstract: When an optical waveguide is formed by focused femtosecond laser pulses in a pure silica glass to induce a refractive index increase region, a pulse width of femtosecond laser pulses are changed, a peak power of femtosecond laser pulses at the focal point is changed, or both the pulse width and the peak power are changed simultaneously. Under conditions where a pulse width of the femtosecond laser pulses is in a range of 210 to 420 fs and a peak power at the focal point is not greater than 8.7×1011 W/cm2, an optical waveguide having a mode field of 10 to 14 &mgr;m such that an aspect ratio is 1 (one) can be obtained. By doing this, it is possible to control a mode field diameter of an optical waveguide and an aspect ratio of the mode field diameter.

Abstract: In the manufacture of an arrayed waveguide grating type optical multiplexer/demultiplexer, respective slab waveguides are provided at input sides and output sides of a waveguide array in a cladding layer formed upon a substrate, which includes plural waveguides whose lengths differ and which are arranged in parallel; and an input waveguide is provided at the input side of the input side slab waveguide, while plural output waveguides are provided at the output side of the output side slab waveguide. The waveguides are made from a material for which the difference between the effective refractive indices for the two polarizations is large, and thereby, when multiplexed light which consists of plural lights of different wavelengths is inputted to said input waveguide, lights which have been separated by wavelength and by polarization are outputted from each of said output waveguides. As a result, it is possible to make a polarization/wavelength multiplex transmission circuit using fewer elements.

Abstract: This two input two output type optical switch includes four one input two output type optical switches which are arranged to oppose one another, each of these one input two output type optical switches including a Y branch portion in which one optical wavegude is branched into two optical wavegudes. And two refractive index adjustment means are provided in the vicinity of each Y branch portion. Switching over of the optical path is performed by half of the refractive index adjustment means functioning alternately. Moreover, a light output intensity variable attenuation function which attenuates by any desired amount the intensity of the light which is being outputted is implemented, at some input port and/or output port, by operating at least one of the refractive index adjustment means which is not currently being used for switching over of the optical path.

Abstract: The present invention relates a method for manufacturing an optical coupler/splitter. A Y-shaped waveguide core is formed by focusing a laser beam into a cladding layer that is formed from a glass material. At least one portion of this Y-shaped waveguide core other than the input port and the output ports is treated as a refractive index adjustment area. After the portions of the Y-shaped waveguide core other than the refractive index adjustment area have been formed by focusing a laser beam, signal light is inputted into the input port of the Y-shaped waveguide core and the signal light outputted from the output ports of the Y-shaped waveguide core are monitored. The refractive index of the refractive index adjustment area is determined based on the result of the monitoring and is adjusted by focusing a laser beam repeatedly.

Abstract: A collimator lens having a low reflectivity and significantly improved durability against high-power light is provided so that optical parts using the collimator lens can be reduced in size and cost lowered. A plurality of optical fibers can be connected to the collimator lens to produce a variety of fiber collimators and optical parts based on the fiber collimator. The collimator lens is made essentially of quarts glass whose refractive index is graded radially so as to increase towards the optical axis and decrease gradually towards the outer periphery. The collimator lens and optical fibers are connected directly by fusion.

Abstract: In the manufacture of an arrayed waveguide grating type optical multiplexer/demultiplexer, respective slab waveguides are provided at input sides and output sides of a waveguide array in a cladding layer formed upon a substrate, which includes plural waveguides whose lengths differ and which are arranged in parallel; and an input waveguide is provided at the input side of the input side slab waveguide, while plural output waveguides are provided at the output side of the output side slab waveguide. The waveguides are made from a material for which the difference between the effective refractive indices for the two polarizations is large, and thereby, when multiplexed light which consists of plural lights of different wavelengths is inputted to said input waveguide, lights which have been separated by wavelength and by polarization are outputted from each of said output waveguides. As a result, it is possible to make a polarization/wavelength multiplex transmission circuit using fewer elements.

Abstract: An optical switch operating on thermooptic effects has a branching section heater for heating a branching section of a core and a branched core heater for heating a branched core. The heaters are controlled separately so that the branching section and the branched core can be heated to respective temperatures so as to minimize insertion loss of inputted light and to prevent outputting light from a port not intended for light output.