Abstract: A wavelength conversion member includes a support, and a wavelength conversion layer that includes a phosphor particle group and a sealing member to seal the phosphor particle group and that is provided directly or through an other layer on the support. A predetermined region, in which a cross-sectional area rate of the phosphor particle group is not less than 50%, is included in an arbitrary cross section of the wavelength conversion layer taken parallel to a thickness direction thereof. The predetermined region includes a rectangular region with a width of 700 ?m and a thickness of 50 ?m from a bottom surface of the wavelength conversion layer when a thickness of the wavelength conversion layer is not less than 50 ?m, or a rectangular region with a width of 700 ?m and a thickness equal to the thickness of the wavelength conversion layer when it is less than 50 ?m.

Abstract: A wavelength conversion member includes a sintered body of a phosphor. An average diameter of pores in an arbitrary cross section falls within a range of not less than 0.28 ?m and not more than 0.98 ?m. A ratio of an area of pores to a whole area in an arbitrary cross section falls within a range of not less than 0.04% and not more than 2.7%. An average diameter of grains of the phosphor in an arbitrary cross section falls within a range of not less than 1 ?m and not more than 3 ?m.

Abstract: A light emitting device includes a laser diode that emits a blue light, and a wavelength conversion part that absorbs a part of light emitted from the laser diode and converts a wavelength thereof. The wavelength conversion part includes a YAG-based single crystal phosphor. Irradiance of light emitted from the laser diode and irradiated on the wavelength conversion part is not less than 80 W/mm2.

Abstract: A light emitting device includes a laser diode that emits a blue light, and a wavelength conversion part that absorbs a part of light emitted from the laser diode and converts a wavelength thereof. The wavelength conversion part includes a YAG-based single crystal phosphor. Irradiance of light emitted from the laser diode and irradiated on the wavelength conversion part is not less than 80 W/mm2.

Abstract: A photoelectric conversion device is provided that has high linearity of output current to illuminance and is applicable to illumination sensors. The photoelectric conversion device outputs appropriate current by complementing first current, which is generated in response to incident light, with complementary current. The complementary current is generated based on second current flowing in response to the light. The second current is generated by a device having the same element area as that of a device that generates the first current. When the second current flows, the complementary current is generated based on a direction of the second current and is then added to the first current.

Abstract: An optical fiber processing apparatus comprises reactors (3, 3a, 3b and 3c) that accommodate optical fiber, a single suction pump (7) having an intake port (19) and an outlet port (21), a storage chamber (5) into which deuterium containing gas is delivered, and a circuit portion (9, 59) including a plurality of valves disposed on a plurality of passages connecting the reactors, the suction pump and the storage chamber. The circuit portion includes a first channel for returning deuterium containing gas inside a reactor chamber to the storage chamber, a second channel for delivering air to the reactor chamber thereby rendering the pressure inside the reactor chamber atmospheric pressure, a third channel for decompression of the reactor chamber and a fourth channel for supplying deuterium containing gas in the storage chamber into the reactor chamber.

Abstract: A treatment method for an optical fiber including accommodating an optical fiber inside a treatment chamber; introducing a deuterium containing gas into the treatment chamber; and in a deuterium treatment step, exposing the optical fiber to atmosphere of the deuterium containing gas. In the deuterium treatment step, a deuterium concentration D in the treatment chamber during the deuterium treatment is calculated from an initial value A of a deuterium concentration in the deuterium containing gas inside the treatment chamber, a concentration B of oxygen in an ambient atmosphere of the treatment chamber, and a concentration C of oxygen in the deuterium containing gas inside the treatment chamber, and the deuterium concentration in the treatment chamber is controlled based on the deuterium concentration D calculated. Other gases such as hydrogen containing gas or nitrogen containing gas may also be used according to the invention.

Abstract: A method of treating optical fiber includes at least a first step of creating a reduced-pressure atmosphere in a space which holds the optical fiber, and a second step of introducing to the space a deuterium-containing gas so as to expose the optical fiber to the gas.

Abstract: A single-mode optical fiber has a cut-off wavelength of 1260 nm or less, a zero-dispersion wavelength in the range of 1300 nm to 1324 nm, a zero-dispersion slope of 0.093 ps/nm2/km or less, a mode field diameter at a wavelength of 1310 nm in the range of 5.5 ?m to 7.9 ?m, and a bending loss of 0.5 dB or less at a wavelength of 1550 nm, the bending loss being produced when the fiber is wound around a 10-mm radius for 10 turns.

Abstract: A single-mode optical fiber has a cut-off wavelength of 1260 nm or less, a zero-dispersion wavelength in the range of 1300 nm to 1324 nm, a zero-dispersion slope of 0.093 ps/nm2/km or less, a mode field diameter at a wavelength of 1310 nm in the range of 5.5 ?m to 7.9 ?m, and a bending loss of 0.5 dB or less at a wavelength of 1550 nm, the bending loss being produced when the fiber is wound around a 10-mm radius for 10 turns.

Abstract: A method of treating optical fiber includes at least a first step of creating a reduced-pressure atmosphere in a space which holds the optical fiber, and a second step of introducing to the space a deuterium-containing gas so as to expose the optical fiber to the gas.

Abstract: A first semiconductor laser element and a second semiconductor laser element are arranged on an identical block, a first electrode of the first semiconductor laser element is in direct contact with the block, and heat radiating effect is high. A second electrode of the second semiconductor laser element is arranged on an insulating dielectric layer, and the block and second semiconductor laser element are electrically insulated. Therefore, irrespective of the material to compose the block, the first semiconductor laser element and the second semiconductor laser element can be independently driven. In addition, the light emitting point distance between the first semiconductor laser element and second semiconductor laser element is limited only by the distance between the electrodes of the respective semiconductor lasers and the positions of light emitting points on the semiconductor laser chip end face and can, therefore, be made as short as possible.

Abstract: A treatment method for an optical fiber including accommodating an optical fiber inside a treatment chamber; introducing a deuterium containing gas into the treatment chamber; and in a deuterium treatment step, exposing the optical fiber to atmosphere of the deuterium containing gas. In the deuterium treatment step, a deuterium concentration D in the treatment chamber during the deuterium treatment is calculated from an initial value A of a deuterium concentration in the deuterium containing gas inside the treatment chamber, a concentration B of oxygen in an ambient atmosphere of the treatment chamber, and a concentration C of oxygen in the deuterium containing gas inside the treatment chamber, and the deuterium concentration in the treatment chamber is controlled based on the deuterium concentration D calculated. Other gases such as hydrogen containing gas or nitrogen containing gas may also be used according to the invention.

Abstract: An optical fiber processing apparatus comprises reactors (3, 3a, 3b and 3c) that accommodate optical fiber, a single suction pump (7) having an intake port (19) and an outlet port (21), a storage chamber (5) into which deuterium containing gas is delivered, and a circuit portion (9, 59) including a plurality of valves disposed on a plurality of passages connecting the reactors, the suction pump and the storage chamber. The circuit portion includes a first channel for returning deuterium containing gas inside a reactor chamber to the storage chamber, a second channel for delivering air to the reactor chamber thereby rendering the pressure inside the reactor chamber atmospheric pressure, a third channel for decompression of the reactor chamber and a fourth channel for supplying deuterium containing gas in the storage chamber into the reactor chamber.

Abstract: A semiconductor laser device includes an active layer and first and second current blocking layers having aligned stripe openings for injecting operating current into the active layer in a current injection area. The second current blocking layer has another opening, through which the first current blocking layer contacts an external cladding layer, in the vicinity of the emission facet of the laser cavity to form a current non-injection area. The first current blocking layer and the external cladding layer have a substantially equal refractive index.

Abstract: A first semiconductor laser element and a second semiconductor laser element are arranged on an identical block, a first electrode of the first semiconductor laser element is in direct contact with the block, and heat radiating effect is high. A second electrode of the second semiconductor laser element is arranged on an insulating dielectric layer, and the block and second semiconductor laser element are electrically insulated. Therefore, irrespective of the material to compose the block, the first semiconductor laser element and the second semiconductor laser element can be independently driven. In addition, the light emitting point distance between the first semiconductor laser element and second semiconductor laser element is limited only by the distance between the electrodes of the respective semiconductor lasers and the positions of light emitting points on the semiconductor laser chip end face and can, therefore, be made as short as possible.

Abstract: A semiconductor laser device includes an active layer and first and second current blocking layers having aligned stripe openings for injecting operating current into the active layer in a current injection area. The second current blocking layer has another opening, through which the first current blocking layer contacts an external cladding layer, in the vicinity of the emission facet of the laser cavity to form a current non-injection area. The first current blocking layer and the external cladding layer have a substantially equal refractive index.

Abstract: A self-sustained pulsation semiconductor laser device has a cladding layer including a pair of cladding layer portions, and a saturable absorbing layer and a buffer layer sandwiched between the pair of cladding layer portions. The semiconductor material for the buffer layer has an intermediate valence band energy between valence band energies of the saturable absorbing layer and the semiconductor material for the cladding layer portion in contact with the buffer layer, to reduce spikes formed in the valence band energy profile. Holes are smoothly injected to an active layer which lases in self-sustained pulsation at a high yield.

Abstract: A p-type saturable light absorbing layer is provided between p-type AlGaInP clad layers. Oxygen is doped in the p-type saturable light absorbing layer to generate non-luminescent recombination center, thereby consuming minority carrier. By this, minority carrier life of the p-type saturable light absorbing layer is lowered without saturation. Therefore, saturable light absorbing amount necessary for self-pulsation can be reduced to achieve a semiconductor laser with low threshold value, low drive current and high reliability.

Abstract: In a semiconductor laser device comprising a plurality of semiconductor layers laminated in a vertical direction on a substrate to form a laser resonator, the laser resonator comprises a saturable absorbing region. A spot size of a light waveguide profile in the vertical direction is greater than 0.4 .mu.m. The laser resonator further comprises first and second reflecting films to provide a reflectivity greater than 50(%).