Abstract: A laser diode module has a laser diode, a lens for condensing the laser beam from the laser diode, an optical fiber for receiving the laser beam from the lens at the end face thereof, and support assembly for supporting the laser diode, the lens, and optical fiber, the support assembly positions the end face of the optical fiber at a deviation position apart from the focal point of the lens by an allowable distance when a temperature of the laser diode module is room temperature and moves the end face of the optical fiber at a close position relatively closer to the focal point than the deviation position when the temperature of the laser diode module rises from the room temperature.

Abstract: A laser diode module has a laser diode, a lens for condensing the laser beam from the laser diode, an optical fiber for receiving the laser beam from the lens at the end face thereof, and support assembly for supporting the laser diode, the lens, and optical fiber, the support assembly positions the end face of the optical fiber at a deviation position apart from the focal point of the lens by an allowable distance when a temperature of the laser diode module is room temperature and moves the end face of the optical fiber at a close position relatively closer to the focal point than the deviation position when the temperature of the laser diode module rises from the room temperature.

Abstract: A semiconductor laser device includes a substrate and a laminated structure formed on a top face of the substrate. The laminated structure includes (a) first and second guide layers and (b) a quantum well structure of compound semiconductor interposed between the first and second guide layers. The quantum well structure serves as a resonator of the device and includes at least one quantum well layer and at least one barrier layer. The quantum well layer has a thickness L.sub.z and the barrier layer has the energy gap larger than the energy gap of the quantum well layer so as to form a energy difference V.sub.0 between the bottom of the conduction band of the quantum well layer and the bottom of the conduction band of the barrier layer. The relationship represented by formula (I) is satisfied:L.sub.z .ltoreq.h / 2 (2m*V.sub.0).sup.1/2 (I)wherein h is Planck's constant and m* is the effective mass of electrons within the quantum well layer.

Abstract: A semiconductor laser device includes a substrate and a laminated structure formed on a top face of the substrate. The laminated structure includes (a) first and second guide layers and (b) a quantum well structure of compound semiconductor interposed between the first and second guide layers. The quantum well structure serves as a resonator of the device and includes at least one quantum well layer and at least one barrier layer. The quantum well layer has a thickness L.sub.z and the barrier layer has the energy gap larger than the energy gap of the quantum well layer so as to form a energy difference V.sub.O between the bottom of the conduction band of the quantum well layer and the bottom of the conduction band of the barrier layer. The relationship represented by formula (I) is satisfied:L.sub.z .ltoreq.h / 2 (2m.sup.* V.sub.O).sup.1/2 (I)wherein h is Planck's constant and m.sup.* is the effective mass of electrons within the quantum well layer.

Abstract: A semiconductor laser device includes a substrate and a laminated structure formed on a top face of the substrate. The laminated structure includes (a) first and second guide layers and (b) a quantum well structure of compound semiconductor interposed between the first and second guide layers. The quantum well structure serves as a resonator of the device and includes at least one quantum well layer and at least one barrier layer. The quantum well layer has a thickness L.sub.z and the barrier layer has the energy gap larger than the energy gap of the quantum well layer so as to form a energy difference V.sub.0 between the bottom of the conduction band of the quantum well layer and the bottom of the conduction band of the barrier layer. The relationship represented by formula (I) is satisfied:L.sub.z <h/2(2m*V.sub.0).sup.1/2 (I)wherein h is Planck's constant and m* is the effective mass of electrons within the quantum well layer.

Abstract: A semiconductor laser device of the present invention includes: a semiconductor substrate having a top face and a bottom face; a multi-layered structure formed on the top face of the semiconductor substrate, the multi-layered structure including an active layer; a stripe-shaped ridge portion which is formed on a first region of a top face of the multi-layered structure and which extends along a cavity length direction; a current blocking layer which covers both side faces of the ridge portion and a second region of the top face of the multi-layered structure; a first electrode formed at least on a top face of the ridge portion; and a second electrode formed on the bottom face of the semiconductor substrate, wherein the current blocking layer includes an insulating film and a resin film formed on the insulating film.

Abstract: In a quantum-well type semiconductor laser device comprising a multi-layered quantum-well layer (active layer) constituted by quantum-well layers and a corresponding number of barrier layers and a pair of optical confinement layers respectively arranged on and under the active layer, since the number of quantum-well layers is limited to one or two, the device has a reduced internal loss, a narrowed far-field angle and a bandgap energy of the quantum-well layers greater than that of the optical confinement layers by more than 160 meV so that it shows a lowered threshold current density. Besides, by selecting a thickness of the quantum-well layers between 3 and 8 nm, the device can be made to oscillate at the first quantum level in order to make the oscillation wavelength highly dependent on temperature and optical output and accordingly produce a high spectral purity.