Abstract: Semiconductor laser structures utilize strain-compensated multiple quantum wells as the laser gain medium to greatly increase the gain and substantially reduce mirror reflectivity constraints in long wavelength (1.3 and 1.55 .mu.m) surface emitting, and other, lasers. The strain-compensated multiple quantum well structures include a plurality of quantum well barrier layer pairs with each quantum well layer being placed under strain and each barrier layer being placed under an equal and opposite strain so that the net overall strain on the quantum well structure is zero. As a result, it can be made as thick as necessary for the lasers to operate efficiently at long wavelengths. Each of the quantum well layers are also preferably p-doped to further increase the optical gain. Another embodiment of the present invention employs the strain-compensated multiple quantum wells in combination with grating-coupling in a surface or edge emitting laser.

Abstract: A laser waveguide medium is provided comprising:a laser glass substrate wherein the substrate is a glass comprising (on an oxide composition basis):______________________________________ Mole % ______________________________________ P.sub.2 O.sub.5 50-70 Al.sub.2 O.sub.3 4-13 Na.sub.2 O 10-35 La.sub.2 O.sub.3 0-6 Ln.sub.2 O.sub.3 >0-6 R'O 0-20 R.sub.2 O 0-18 ______________________________________wherein Ln.sub.2 O.sub.3 is the sum of the oxides of active lasing lanthanides of atomic numbers 58-71, R'O is the sum of oxides of Mg, Ca, Cr, Ba, Zn and Pb, and R.sub.2 O is the sum of oxides of Li, K, Rb and Cs; anda waveguide region embedded in the substrate, the waveguide region having a higher refractive index than the substrate and the waveguide region having an inlet region through which light can enter and an outlet region through which light can exit.

Abstract: A cavity in which exciting lamps and a laser rod are disposed is provided in the substantially central position of the section of a cylindrical casing. A heat exchanger comprises a multiplicity of cooling fins which surround the periphery of the cavity are integrally formed of an outer wall so that air paths are formed through and between the cooling fins in an axial direction of the cylindrical casing and coolant is circulated through a space between the cavity and the outer wall. A cooling fan is disposed in the rear of said cylindrical casing for blowing air toward the heat exchanger.

Abstract: Radiating light from a semiconductor laser element is radiated in a direction normal to the surface of a photodetector substrate. The semiconductor laser element and photodetector are disposed on the same plane. Specifically, a reflecting mirror surface formed of a slanting surface of (111) lattice plane having a ridge line of <110> direction is disposed on a silicon substrate of (100) lattice plane having an off-angle of 4.degree. to 14.degree. about an axis of <110> direction or on a silicon substrate of (511) lattice plane having an off-angle of 1.degree. to 11.degree. about an axis of <110> direction. The semiconductor laser chip is disposed at a position opposing to the reflecting mirror surface.

Abstract: In a of modulating a feedback signal in an optical amplifier, employing a laser diode LD, which can directly amplify an optical signal, the amplified optical signal is modulated by the feedback signal SV which is controlled in such a way as to compensate for the saturation characteristics of the laser diode LD to correctly modulate the feedback signal even if the laser diode is nearly saturated due to aging or fluctuations in temperature.

Abstract: In a semiconductor laser having a p-type cladding layer consisting of GaInP or AlGaInP, an operating voltage is decreased. In a semiconductor laser formed on a GaAs substrate and having a p-type cladding layer consisting of GaInP or AlGaInP and a p-type contact layer consisting of GaAs or GalnAs, p-type buffer layers are formed between the p-type cladding layer and the p-type contact layer, which consists of a compound containing both arsenic (As) and phosphorus (P) and having a medium bandgap between those of the two layers.

Abstract: Method and device for generating optical pulses.According to the invention, in order to generate an optical signal in the form of optical pulses, a semiconductor laser (2) is made to function as gain commutation, and a portion of the light produced by this laser is reinjected into the laser. The light to be reinjected is previously filtered by an optical filter (12) which is tuned to one of the modes of the laser. Another portion of the light produced by the laser is used as an optical signal after having been filtered this portion by the optical filter.

Abstract: A laser diode suitable for blue-green light emission utilizing type II heterojuctions of II-VI compound semiconductors. The laser diode comprises a layer 24 for confining electrons, a layer 26 for confining holes, and a quantum well layer which is formed bewteen the electron confinement layer 24 and the hole confinement layer 26 and allows the confined electrons and holes to recombine therein. The laser also comprises an electron barrier layer 23 and a hole barrier layer 27 for preventing diffusion of the electrons and holes beyond the barriers. The light emitted by the recombination is confined between the n-cladding layer 22 and a p-cladding layer 28.

Abstract: A system for producing laser output from a solid-state laser is described. The laser output comprises two orthogonally polarized axial modes of light at different frequencies having linear polarization. In one embodiment, the two modes are at different frequencies and can be merged together to produce energy waves of variable frequency. This device has applications in microwave generation and velocity measurements.

Abstract: A doubler for a pulsed multimode laser diode. A controllable feedback loop controls the laser output such that one of the output wavelengths, or the average of two of them, fall within the acceptance bandwidth of a non-linear optical medium. Alternatively, radiation emitted from the pulsed laser is reflected over a path length such that reflected energy reenters the laser during the build-up of a following pulse.

Abstract: A method for selecting a semiconductor laser is provided which contributes to improved productivity of a highly reliable semiconductor laser of prolonged lifetime, and which includes the steps of: (a) measuring highest peak intensity, Ia, and next highest peak intensity, Ib, of an interference fringes pattern of laser radiation of each semiconductor laser using an interferometer to find a damping ratio of visibility of the interference fringes pattern, .gamma.=Ib/Ia; and (b) selecting a semiconductor exhibiting self-pulsation by selecting a semiconductor laser which emits laser radiation whose damping ratio of visibility, .gamma., is 0.5 or less.

Abstract: A laser device includes a glass optical fiber secured in position to capture light output from the laser. The fiber is secured in position with solder directly to the glass of the fiber without any metallization of the fiber. The solder-only technique satisfies the critical requirement for preventing fiber movement over the lifetime standard for laser device with multimade lasers and multimode fibers.

Abstract: A semiconductor laser includes: a first conductivity type semiconductor substrate; a first conductivity type lower cladding layer disposed on the substrate; a quantum well structure disposed on the lower cladding layer; a second conductivity type upper cladding disposed on the quantum well structure; a ridge including a stripe-shaped second conductivity type semiconductor of a length extending in the laser resonator length direction reaching neither semiconductor laser facet and disposed on the upper cladding layer; disordered regions, i.e, window structures, formed in the quantum well structure in the vicinity of the laser resonator facets by ion-implanting a dopant impurity; and a first conductivity type current blocking layer, disposed on the upper cladding layer on the disordered quantum well structure layer, burying the ridge.

Abstract: A monolithically integrated photonic circuit combining a semiconductor source of excitation light with an optically active waveguide formed on the substrate. The optically active waveguide is preferably formed of a spin-on glass to which are added optically active materials which can enable lasing action, optical amplification, optical loss, or frequency conversion in the waveguide, depending upon the added material.

Abstract: An apparatus and method for producing laser radiation from a vertical cavity semiconductor laser are disclosed. A preferred embodiment includes a quantum-well region formed over a semiconductor substrate. A first reflective surface is formed over the quantum-well region, and a second reflective surface is formed over the substrate, opposite the first reflective surface, forming a laser cavity. The quantum-well region is optically pumped, producing laser oscillation. The absorbed pump power causes a thermal lensing effect within the semiconductor material, stabilizing the transverse spatial mode of the laser cavity. The invention has applications in optical communication and laser printing.

Abstract: A semiconductor optical device includes a first semiconductor layer, and a diffraction grating disposed on the first semiconductor layer. The diffraction grating includes portions of a superlattice layer grown on the first semiconductor layer and including alternatingly arranged second semiconductor layers of a semiconductor material in which mass transport hardly occurs, during growth of other semiconductor layers and third semiconductor layers of a semiconductor material different from the material of the second semiconductor layers. The device includes a fourth semiconductor layer burying the diffraction grating. In this structure, since the second semiconductor layers are included in the diffraction grating, the shape of the diffraction grating is maintained during the vapor phase deposition of the fourth semiconductor layer. Therefore, the thickness, amplitude, and pitch of the diffraction grating that determine the optical coupling constant are controlled with high precision.

Abstract: A surface emission type semiconductor light-emitting device includes a substrate, a distributed Bragg reflector formed on the substrate, a light-emitting region formed on the distributed Bragg reflector, a first contact layer, formed on a portion of the light-emitting region and transparent to a wavelength of light emitted from the light-emitting region, for supplying a current to the light-emitting region, and a second contact layer, formed on the light-emitting region to cover a side portion of the first contact layer, for forming a current blocking barrier between the light-emitting region and the second contact layer and supplying the current to the first contact layer.

Abstract: A tunable laser system having a wide tunable range, and narrow line widths, achieves relatively high output powers. The tunable laser system includes a master optical parametric oscillator which generates a seed beam, and a power optical parametric oscillator which is responsive to the seed beam to generate a narrow line width, high power output beam. The master OPO and power OPO comprise gain media consisting of BBO, tunable over a range from about 400 nanometers to more than 2000 nanometers. The master OPO includes line narrowing elements, such as a tunable grating, which limits the line width of the output beam to less than one wave number (centimeter.sup.-1). Pump energy is supplied to the master OPO and power OPO using a Nd:YAG laser with a harmonic generator, so that the second, third, or fourth harmonics of the primary 1064 nanometer line of YAG can be used to pump the BBO crystals. The power OPO may be an unstable resonator.

Abstract: A semiconductor laser device, and method for making such, having higher operating temperatures than previously available. A semiconductor epitaxial layer is bonding to a cleaving assembly which allows the epitaxial layer to be manipulated without use of traditional substrate forms. The resulting semiconductor laser is bonded to a metal portion which serves as a heat sink for dissipating heat from the active lasing region. The resulting semiconductor lasers can be cooled by thermoelectric cooling modules, thus eliminating the necessity of using more bulky cryogenic systems.

Abstract: A semiconductor laser includes a semiconductor substrate of a first conductivity type having opposite front and rear surfaces, a double-heterojunction structure including a first conductivity type lower cladding layer, an undoped active layer, and an upper cladding layer of a second conductivity type, opposite the first conductivity type, successively disposed on the front surface of the semiconductor substrate wherein the double-heterojunction structure is a mesa having opposite sides, and a light and current confinement structure disposed on the opposite sides of the mesa for confining laser light and laser driving current within the mesa. The confinement structure includes a first conductivity type mesa embedding layer, a second conductivity type mesa embedding layer, and a semi-insulating InP layer which are successively disposed on the semiconductor substrate contacting the opposite sides of the mesa.