Abstract: An optical transmitter includes a laser configured to emit light, a power of the light increasing with temperature decreasing, a Faraday rotator configured to rotate a polarization direction of the light in accordance with the temperature, and a first polarizer that has a principal axis inclined at a given angle and inputs the light output from the Faraday rotator.

Abstract: An optical transmitter includes a laser configured to emit light, a power of the light increasing with temperature decreasing, a Faraday rotator configured to rotate a polarization direction of the light in accordance with the temperature, and a first polarizer that has a principal axis inclined at a given angle and inputs the light output from the Faraday rotator.

Abstract: An air bag, when in a flattened condition, has a longitudinally extending upper edge and a longitudinally extending lower edge. The longitudinally extending upper and lower edges extend on and along first and second imaginary lines respectively. The air bag comprises a plurality of expandable portions that include a larger expandable portion that has upper and lower edges respectively extending on and along the first and second imaginary lines and a smaller expandable portion that has an upper edge extending on and along the first imaginary line and a lower edge spaced from the second imaginary line by a given distance; and a non-expandable portion having a size-compensating part that extends from the lower edge of the smaller expandable portion to the second imaginary line.

Abstract: A light source module including: an LD element outputting a laser light; a lens receiving the laser light and outputting a focused light; an optical filter having transmission wavelength characteristics, inputting the focused light, and outputting a transmitted light and a reflected light based on the transmission wavelength characteristics, a light-receiving element detecting the reflected light which passes thorough the lens and generating a detection signal; and a control unit configured to control an output wavelength of the LD element based on the detection signal.

Abstract: An air bag, when in a flattened condition, has a longitudinally extending upper edge and a longitudinally extending lower edge. The longitudinally extending upper and lower edges extend on and along first and second imaginary lines respectively. The air bag comprises a plurality of expandable portions that include a larger expandable portion that has upper and lower edges respectively extending on and along the first and second imaginary lines and a smaller expandable portion that has an upper edge extending on and along the first imaginary line and a lower edge spaced from the second imaginary line by a given distance; and a non-expandable portion having a size-compensating part that extends from the lower edge of the smaller expandable portion to the second imaginary line.

Abstract: An optical module comprises a splitting element that splits light outputted from a light source; a first monitoring means that detects the intensity of light split by the splitting element; a polarization control means that switches the polarization state of light outputted from the splitting element based on a control signal; a filter means that accepts light outputted by the polarization control means as input, and whereof the characteristic changes depending on the polarization state of the input light; and a second monitoring means that detects the intensity of the light transmitted through the filter means.

Abstract: Light incident on an input optical fiber is separated into p-polarized light and s-polarized light by a birefringent crystal. A voltage to be applied to a liquid crystal element having electrodes associated with the ray axes of the polarized light waves is controlled in order to convert the p-polarized light into s-polarized so that both the polarized light waves will be s-polarized light. A polarized-wave separation film transmits p-polarized light and reflects s-polarized light. When both the polarized light waves propagated through the liquid crystal element are s-polarized light, the light reflected from the polarized-wave separation film is reflected from a total-reflection film, and reflected again from the polarized-wave separation film. The resultant light falls on the birefringent crystal again via the liquid crystal element, and is restored to non-polarized light by the birefringent crystal. The non-polarized light then falls on a first output optical fiber.

Abstract: Light incident on an input optical fiber is separated into p-polarized light and s-polarized light by a birefringent crystal. A voltage to be applied to a liquid crystal element having electrodes associated with the ray axes of the polarized light waves is controlled in order to convert the p-polarized light into s-polarized so that both the polarized light waves will be s-polarized light. Otherwise, the s-polarized light is converted into p-polarized light so that both the polarized light waves will be p-polarized light. A polarized-wave separation film located behind the liquid crystal element transmits p-polarized light and reflects s-polarized light. When both the polarized light waves propagated through the liquid crystal element are s-polarized light, the light reflected from the polarized-wave separation film is reflected from a total-reflection film, and reflected again from the polarized-wave separation film.

Abstract: A package for hermetically sealing a semiconductor laser which outputs light having a wavelength of 1.1 ?m or more is filled with a gas containing an oxidizing gas such as oxygen or ozone. The oxidizing gas in the package oxidizes hydrogen in the package to prevent hydrogen embrittlement of electrodes that applies stress on electrodes and to suppress variation in the emission wavelength which would otherwise result from the application of stress.

Abstract: An optical module comprises a splitting element that splits light outputted from a light source; a first monitoring means that detects the intensity of light split by the splitting element; a polarization control means that switches the polarization state of light outputted from the splitting element based on a control signal; a filter means that accepts light outputted by the polarization control means as input, and whereof the characteristic changes depending on the polarization state of the input light; and a second monitoring means that detects the intensity of the light transmitted through the filter means.

Abstract: A package for hermetically sealing a semiconductor laser which outputs light having a wavelength of 1.1 &mgr;m or more is filled with a gas containing an oxidizing gas such as oxygen or ozone. The oxidizing gas in the package oxidizes hydrogen in the package to prevent hydrogen embrittlement of electrodes that applies stress on electrodes and to suppress variation in the emission wavelength which would otherwise result from the application of stress.

Abstract: Disclosed herein is a laser diode module having a thermoelectric cooling element, a laser diode, and a thermistor in a housing. The thermoelectric cooling element has a first surface and a second surface between which heat exchange is performed. The first surface is in close contact with an inner surface of the housing. A base is provided on the second surface in close contact therewith. A laser carrier and a thermistor carrier are provided on the base in close contact therewith. The laser diode and the thermistor are provided on the laser carrier and the thermistor carrier in close contact therewith, respectively. A portion of the base in the vicinity of the laser carrier is thermally connected to the housing by a metal plate, for example, thereby allowing high-precision temperature control of the laser diode.

Abstract: An optical module includes a first level detecting part having a semi-transparent structure and receiving a light signal emitted from a light-emitting element, a second level detecting part receiving the light signal which penetrates through the first level detecting part and passes through an optical filter, and a control part controlling an operation temperature of the light-emitting element on the basis of electric signals output from the first and second level detecting parts.

Abstract: A movable blade of a turbine, which has a plurality of stages each provided with movable and stationary blades mounted to a turbine rotor, comprises a movable blade body having a leading edge portion, with respect to a turbine steam flow, and an erosion protective piece which is formed to be continuously integrally with the leading edge portion of the movable blade body so as to be protruded therefrom. The leading edge portion and the erosion protective piece are subjected to a surface hardening treatment such as flame hardening treatment.

Abstract: A Peltier control circuit detects a temperature of a device combined with a Peltier device and controls a current flowing through the Peltier device so as to keep the temperature of the device at a predetermined value. The circuit has a temperature sensing section for detecting the temperature of a device, a comparing section for comparing a temperature detection value with a predetermined temperature reference value, a limiting section for providing a comparison output with the limitation of a current flowing through the Peltier device and providing the limitation with a predetermined temperature characteristics, and a driving section for providing the Peltier device with an input or output driving current in accordance with the comparison output via the limiting section.

Abstract: An optical isolator has a low-profile construction. Two rod-like permanent magnets are on two sides of a Faraday element in parallel to an optical axis. The two permanent magnets are sandwiched and fixed between two ferromagnetic frames each having a light path hole therein. The ferromagnetic frames are each provided with a protrusion for guiding the magnetic flux generated by the permanent magnets to the Faraday element.

Abstract: A semiconductor laser module includes a semiconductor laser assembly formed by containing a semiconductor laser in a package, a lens assembly fixed by welding to the package of the semiconductor laser assembly, and a fiber assembly fixed by welding to the lens assembly. The semiconductor laser assembly includes a base fixed to the package and a carrier fixed to the base. The semiconductor laser is mounted on the carrier. A lens holder of the lens assembly is spot-welded to the package at a plurality of positions set below the upper surface of the base.

Abstract: Disclosed herein is a laser diode module having a thermoelectric cooling element, a laser diode, and a thermistor in a housing. The thermoelectric cooling element has a first surface and a second surface between which heat exchange is performed. The first surface is in close contact with an inner surface of the housing. A base is provided on the second surface in close contact therewith. A laser carrier and a thermistor carrier are provided on the base in close contact therewith. The laser diode and the thermistor are provided on the laser carrier and the thermistor carrier in close contact therewith, respectively. A portion of the base in the vicinity of the laser carrier is thermally connected to the housing by a metal plate, for example, thereby allowing high-precision temperature control of the laser diode.

Abstract: A Peltier control circuit detects a temperature of a device combined with a Peltier device and controls a current flowing through the Peltier device so as to keep the temperature of the device at a predetermined value. The circuit has a temperature sensing section for detecting the temperature of a device, a comparing section for comparing a temperature detection value with a predetermined temperature reference value, a limiting section for providing a comparison output with the limitation of a current flowing through the Peltier device and providing the limitation with a predetermined temperature characteristics, and a driving section for providing the Peltier device with an input or output driving current in accordance with the comparison output via the limiting section.

Abstract: A melody generating system is fabricated from a switch unit operative to produce an activation signal, an analog signal producing unit responsive to the activation signal and producing an analog melody signal carrying pieces of melody information used for reproducing a melody and a sound unit responsive to the analog melody signal for reproducing the melody, wherein the analog signal producing unit comprises an analog signal producing circuit integrated on a single semiconductor chip and responsive to the activation signal for producing a read out controlling signal and a memory circuit storing the pieces of melody information and responsive to the read out controlling signal for producing a digital melody information carrying signal, and the analog signal producing circuit is further responsive to the digital melody information carrying signal for producing the analog melody signal, so that a system supplier easily copes with a request for a new melody by changing the pieces of melody information stored in t