Abstract: An impact test apparatus includes a holding device for holding a test piece at an arbitrary holding force, an impact applying device for applying an impact force to the test piece held by the holding device, a force sensor for sensing the impact force applied to the test piece by the impact applying device, a high-speed camera for detecting a displacement of the test piece when applied with the impact force by the impact applying device, and an output device for synchronizing a signal from the force sensor with a signal from the high-speed camera and outputting an impact stress-strain characteristic curve when the impact force is applied to the test piece.

Abstract: A semiconductor laser element is fixed onto a submount by forming a metallic thin film at a region on a surface of a p-side electrode of the semiconductor laser element. A periphery of the thin metallic thin film is recessed from a periphery of the p-side electrode by a predetermined width. The metallic thin film is thermally processed together with the p-side electrode for increasing a size of the grains and connected through a solder layer to the submount. Parts of the p-side electrode and the submount, the metallic thin film and the solder layer include Au for improving a cushion function of the semiconductor laser device.

Abstract: A communication apparatus includes: a memory (418) that holds CA information A (301a) including (ú@) a CA certificate A (106a) indicating that an AP server certificate A (402a) that indicates the validity of an application server (401) is valid and (úA) a URL B (302b) indicating the URL of a download server B (406b) where CA information B (301b) including the next valid CA certificate B (106b) is stored; a server authentication unit (416) that verifies the AP server certificate A (402a) using the CA certificate A (106a); and a CA information update unit (417) that obtains the CA information B (301b) from the download server B (406b) indicated by the URL B (302b), wherein when the CA certificate A (106a) becomes revoked, the server authentication unit (416) thereafter authenticates the application server (401) using the CA certificate B (106b) included in the CA information B (301b) obtained by the CA information update unit (417).

Abstract: A semiconductor laser module includes a distributed-feedback laser. When a predetermined transmission loss, a predetermined number of channels, and a predetermined modulation factor per channel are given, a cavity length of the distributed-feedback laser satisfies a condition that a distortion is less than a predetermined distortion level and a carrier-to-noise ratio is more than a predetermined value based on a relation between transmission loss, number of channels, modulation factor per channel, and the cavity length of the distributed-feedback laser.

Abstract: A semiconductor laser module including a semiconductor laser device having an integrated diffraction grating configured to output a multiple mode laser beam in the presence of a driving current, an optical fiber configured to guide the multiple mode laser beam to an output of the laser module, and an optical attenuation device configured to attenuate the multiple mode laser beam by an amount sufficient to provide a predetermined output power from the output of the laser module. The optical attenuation device may be an optical coupling lens offset from an optimum coupling position by an amount sufficient to provide the predetermined output power, or an optical attenuator interrupting the optical fiber and configured to attenuate the multiple mode laser beam by an amount sufficient to provide the predetermined output power.

Abstract: A semiconductor laser device, module, and method for providing light suitable for providing an excitation light source for a Raman amplifier. The semiconductor laser device includes an active layer configured to radiate light, a spacer layer in contact with the active layer and a diffraction grating formed within the spacer layer, and configured to emit a light beam having a plurality of longitudinal modes within a predetermined spectral width of an oscillation wavelength spectrum of the semiconductor device. A plurality of longitudinal modes within a predetermined spectral width of an oscillation wavelength spectrum is provided by changing a wavelength interval between the longitudinal modes and/or widening the predetermined spectral width of the oscillation wavelength spectrum.

Abstract: A data source has a data converting part for converting inputted data to predetermined data packets. A data buffer stores the data packets. A descriptor list stores a descriptor to which predetermined addresses are added, where a method of sending the data packets is described. A FIFO stores the predetermined addresses in a first-in first-out mode. A data sending part receives start instructions from the data converting part, refers to a predetermined address in which reference is not made yet in the FIFO, fetches data packets corresponding to the descriptor from the data buffer in accordance with a method of sending the descriptor indicated by the predetermined address, generates a send packet from the data packet and outputs the data packet. An end-of-send notice to the data converting part is also send when the output of the send packet is ended.

Abstract: A semiconductor laser module has a Fabry-Perot type semiconductor laser device, an optical fiber, and first and second lenses. The tip of the optical fiber, on which the laser beam falls, is askew polished. The optical fiber is fixed in such a manner that the axis of the optical fiber makes an angle with respect to an optical axis of the laser beam. Coatings that avoid reflection are formed on the tip of the optical fiber, and on the first and second lenses.

Abstract: A semiconductor laser device which has a diffraction grating partially provided in the vicinity of an active layer formed between a radiation-side reflection film provided on a radiation-side end surface of a laser beam and a reflection film provided on a reflection-side end surface of the laser beam, and which outputs a laser beam having a desired oscillation longitudinal mode based on a wavelength selection characteristic of at least the diffraction grating. The diffraction grating is formed in isolation with an isolation distance of Ls=15 ?m from the radiation-side reflection film.

Abstract: A package accommodates an LD device for emitting laser light with the center wavelength of which is in a range of 1300 to 1440 nm and airtight seals a light path extending from the LD device to an incident end of an optical fiber. The package is filled with a nitrogen gas at a standard atmospheric pressure with the amount of moisture limited to a value lower than 100000 ppm by volume or less. Therefore, the amount of moisture in the light path for laser light within the package is limited to 100000 ppm by volume or less.

Abstract: A diffraction grating is provided in the vicinity of a GRIN-SCH-MQW active layer formed between a radiation side reflection coating provided on a radiation end face of a laser beam and a reflection coating provided on a reflection end face of the laser beam, and on the radiation side reflection coating side. An n-InP layer which covers the upper part of the diffraction grating is also provided, so that the current from the p-side electrode is prevented from being injected to the vicinity of the diffraction grating by the n-InP layer. An n-InPGaAsP diffusion prevention layer forms a non-current injection area so as to suppress alloying with the p-side electrode.

Abstract: A compressive strain GRIN-SCH-MQW active layer and a tensile strain GRIN-SCH-MQW active layer are laminated, and there are provided a diffraction grating formed in the vicinity of the compressive strain GRIN-SCH-MQW active layer and a diffraction grating formed in the vicinity of the tensile strain GRIN-SCH-MQW active layer, between the radiation end face and the reflection end face of the laser beam. A laser beam obtained by polarization-multiplexing a laser beam in the TE mode generated in the compressive strain GRIN-SCH-MQW active layer and a laser beam in the TE mode generated in the tensile strain GRIN-SCH-MQW active layer, and having a plurality of oscillation longitudinal modes of not larger than a predetermined output value is output by the wavelength selection characteristic of the diffraction gratings.

Abstract: A semiconductor laser device and module for use in a dense wavelength division multiplexed optical communications system are shown. The laser device preferably has cavity lengths greater than 1000 ?m, and compressive strain multi-quantum well active layer, and front-facet reflectivity of less than about 4%. Higher optical outputs by longer cavity lengths are achieved. Preferred modules use these laser diodes with external wavelength-selective reflectors that have narrow bandwidths of 3 nm or less, and which include a plurality of longitudinal mode subpeaks within the bandwidth. Relationships between reflectivity value of the front facet and the peak reflectivity of the wavelength-selective reflector for long cavity length laser device are also disclosed, with the relationships providing higher output power along with a stabilized output spectrum.

Abstract: A semiconductor laser device which has a diffraction grating partially provided in the vicinity of an active layer formed between a radiation-side reflection film provided on a radiation-side end surface of a laser beam and a reflection film provided on a reflection-side end surface of the laser beam, and which outputs a laser beam having a desired oscillation longitudinal mode based on a wavelength selection characteristic of at least the diffraction grating. The diffraction grating is formed in isolation with an isolation distance of Ls=15 ?m from the radiation-side reflection film.

Abstract: An n-side electrode, an n-substrate, an n-buffer layer, a GRIN-SCH-MQW active layer, a p-spacer, a p-cladding layer, a p-contact layer, and a p-side electrode are laminated one on top another in that order. Above the n-buffer layer, the GRIN-SCH-MQW layer and the p-spacer layer occupy a narrower area than the n-substrate in a direction that is at right angles to the laser emission direction, wherein the remaining area is occupied by a p-blocking layer and an n-blocking layer. Within the p-spacer layer are embedded a first diffraction grating and a second diffraction grating. Between the first and the second diffraction grating and the p-side electrode is provided a current non-injection area.

Abstract: A semiconductor laser device includes an active layer configured to radiate light, a light reflecting facet positioned on a first side of the active layer, and a light emitting facet positioned on a second side of the active layer thereby forming a resonator between the light reflecting facet and the light emitting facet. A diffraction grating is positioned within the resonator along a portion of the length of the active layer and the laser device is configured to operate as a multiple mode oscillation device. A window structure is provided between an end of the active layer and one of the light reflecting and light emitting facets, and the window structure is configured to reduce a reflectivity of the one of the light reflecting and light emitting facets.

Abstract: A semiconductor laser device having two active-layer stripe structures includes an n-InP substrate, an n-InP clad layer, a lower GRIN-SCH layer, an active layer, an upper GRIN-SCH layer, a p-InP clad layer, and a p-InGaAsP contact layer grown in this order, in a side cross section cut along one of the stripe structure. A high-reflection film is disposed on a reflection-side end surface, and a low-reflection film is disposed on an emission-side end surface. A p-side electrode is disposed on only a part of the upper surface of the p-InGaAsP contact layer so that a current non-injection area is formed on an area absent the p-side electrode.

Abstract: A semiconductor laser device including a light reflecting facet positioned on a first side of the semiconductor device, a light emitting facet positioned on a second side of the semiconductor device thereby forming a resonator between the light reflecting facet and the light emitting facet, and an active layer configured to radiate light in the presence of an injection current, the active layer positioned within the resonator. A wavelength selection structure is positioned within the resonator and configured to select a spectrum of the light including multiple longitudinal modes, the spectrum being output from the light emitting facet. Also, an electrode positioned along the resonator and configured to provide the injection current, and a tuning current that adjusts a center wavelength of the spectrum selected by the wavelength selection structure.

Abstract: A semiconductor laser element for outputting a laser beam, a thermistor for measuring the temperature of the semiconductor laser element, and a carrier having an insulating characteristic and a high heat conductivity, in which the semiconductor laser element and the thermistor are joined to the carrier through a multi-layer film including a gold film so that the temperature of the semiconductor laser element is accurately measured and controlled.

Abstract: A cavity length is determined on the basis of a relationship of electric drive power to a range of optical output power over 50 mW, for cavity length to be constant as a parameter in a range over 1000 &mgr;m, so that the electric drive power is vicinal to a minimum thereof in correspondence to a desirable optical output power. If the optical output is 360 mW for example, a cavity length of 1500 &mgr;m is determined to be selected.