摘要:
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.
摘要:
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 μm from the radiation-side reflection film.
摘要:
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.
摘要:
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.
摘要:
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 &mgr;m, and compressive strain multi-quantum well active layer, and front-facet reflectivity of less than about 4%. Higher optical outputs and 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.
摘要:
A video and voice signal processing apparatus is provided. The apparatus includes a signal receiving circuit for receiving an input signal containing a plurality of frames, each frame having an encoded voice signal block and an encoded video signal block. The signal receiving circuit separates the encoded voice signal block from the encoded video signal block in each frame. A voice signal processor converts the encoded voice signal block into a voice signal. Also included is a video extracting circuit which decimates a plurality of encoded video signal blocks and extracts one of the encoded video signal blocks as a representative video signal. A video signal processor converts the representative video signal into a video signal.