Abstract: Deleterious feedback reflections from a power amplifier into a laser master oscillator are eliminated by interposing a nonreciprocal frequency shifter between the oscillator and amplifier, which shifts the laser frequency by more than twice the bandwidth of the laser oscillator resonant cavity.

Abstract: Plural planar optical devices are simultaneously pumped by a single pumping source. Various arrangements for accomplishing such pumping are disclosed. By utilizing these arrangements, the topology and routing of integrated arrays including optical devices are simplified.

Abstract: A semiconductor laser with a semiconductor multilayer has at least one double heterostructure. There area pair of cladding layers and an active layer and, where a bandgap energy of the cladding layers is E.sub.1 and that of the active layer is E.sub.2, these bandgap energies satisfy a relation substantially E.sub.1 .gtoreq.2.times.E.sub.2. The semiconductor laser produces green SHG (second harmonic generation) light and the efficiency of producing such light is high because the cladding layers absorb substantially no SHG light.

Abstract: A polarization insensitive fiber laser. A pair of 45 degree Faraday rotators are positioned on either end of the fiber gain source. The resulting laser is insensitive to external perturbations with respect to known entrance and exit polarization states of the laser light. Modelocking, both passive and active, is possible. Configuration wherein the fiber is a combination of polarization preserving and Erbium-doped, and a saturable absorber is included provide a self-starting, polarization insensitive modelocked laser.

Abstract: A phased array of semiconductor laser elements is provided in which the percentage of light which propagates into different diffractive orders is modified by an optical element. The diode laser includes a body of a semiconductor material having an active region therein which is adapted to generate radiation and emit the radiation form a surface of the body, and separate reflecting mirrors at opposite sides of the active region with at least one of the mirrors being partially transparent to the generated light to allow the light generated in the active region to be emitted therethrough. The optical element may take the form of a modification in the arrangement of the semiconductor laser elements, or an array of microprisms, or an external mirror to modify the percentage of light which propagates into different diffractive orders.

Abstract: A length of an optical fiber having a core and a surrounding cladding is held by a block with a portion of said length having substantially all of its cladding removed on one side of the portion and being exposed, and an index overlay perturbation pad is mounted near and substantially parallel to the portion. A translator moves the pad between a first position in which the pad is sufficiently remote from the portion to allow total internal reflection in the portion and a second position in which the pad is sufficiently close to the portion to allow light to escape from the core. The pad may be made of a metal for polarized modulation, or of a dielectric for unpolarized modulation. The optical switch provides very fast switching for a O-switched fiber laser.

Abstract: A semiconductor laser source using a strained active layer of GaAsP or InGaAsP or AlGaAsP to obtain semiconductor laser sources that emit TM-polarized light in the wavelength range of 600-870 nm. Preferably, the active layer is flanked by confining layers of AlGaAs or (AlGa).sub.0.52 In.sub.0.48 P. The active layer under proper conditions can also emit TE-polarized light. Hence, arrays of side-by-side orthoginally-polarized emitters, or switchable polarized emitters are feasible.

Abstract: This invention relates to a light-emitting apparatus, a photosemiconductor apparatus and a method for producing a photosemiconductor wherein the light-emitting apparatus for emitting light on an object comprises a substrate; a light-emitting element provided on the substrate; an optical member provided on a predetermined position to the substrate; a light-receiving element provided on the substrate, the light-receiving element receiving a part of light beam emitted from the light-emitting element on the object via the optical member; and means for controlling a quantity of the beam projected from the light-emitting element on the object, based on an output signal from the light-receiving element.

Abstract: A multiwavelength upconversion waveguide laser producing visible or ultraviolet wavelength radiation comprising a semiconductor laser diode producing relatively long wavelength radiation, a channel waveguide having a thin film material which converts the relatively long wavelength radiation into visible or ultraviolet wavelength radiation, and a optical resonator which recirculates the visible or ultraviolet wavelength radiation. The optical resonator may use an output optical coating or one or more Bragg grating reflectors as an output coupler. One or more optical resonators may be used to produce one or more visible or ultraviolet radiation wavelengths. One or more independently controllable lightwave modulators are used to modulate the visible or ultraviolet wavelength radiation.

Abstract: A new injection-controlled laser resonator incorporates self-filtering and self-imaging characteristics with an efficient injection scheme. A low-divergence laser signal is injected into the resonator, which enables the injection signal to be converted to the desired resonator modes before the main laser pulse starts. This injection technique and resonator design enable the laser cavity to improve the quality of the injection signal through self-filtering before the main laser pulse starts. The self-imaging property of the present resonator reduces the cavity induced diffraction effects and, in turn, improves the laser beam quality.

Abstract: An optical gain medium comprises a multi-phase system wherein: a first phase is an electromagnetic radiation emitting and amplifying phase (16) that is comprised of doped semiconductor nanocrystals; a second phase is an electromagnetic radiation scattering phase (14); and a third phase is a substantially transparent (at the wavelengths of interest) matrix phase (12). The emission phase may consist of ZnS nanoparticles that are doped with Mn.sup.2+, the scattering phase may comprise TiO.sub.2 or Al.sub.2 O.sub.3 nanoparticles, and the matrix phase may comprise a glass or polymer body, layer or coating. At least one dimension of a body, layer, or coating comprised of the gain medium may be less than a scattering length associated with the scattering phase.

Abstract: A laser has been developed with an active laser element which, in certain aspects, employs no mirrors but instead has a lasant rod with ends formed to produce total or nearly total internal reflection and an output window surface at one end from which a laser beam exits the device. In one aspect a rod end or ends are formed in the shape of polyhedrons whose surfaces reflect oscillating radiation. Also disclosed is a laser with an active laser emitter with a lasant rod with a first end formed in the shape of a polyhedron and a second flat end adjacent to or in contact with a plate or plates of solid reflective, coated or uncoated material, which are next to each other or spaced apart by spacer apparatus, e.g. rings. Such a laser emitter may be used in a laser device without other mirrors or reflectors.

Abstract: A solid state laser apparatus is capable of suppressing a mode hopping phenomena by restricting longitudinal modes except a fundamental mode, thereby providing a very stable output. The solid state laser apparatus includes such components as a semiconductor laser emitting a pumping radiation for exciting a lasant material, a lens systems for focusing the pumping radiation and an optical resonator including a concave mirror. The lasant material may be formed of Nd:YVO.sub.4 doped with approximately 1 at % of Nd and a non-linear optical element may be formed of KTiOPO.sub.4 with an inclined c-axis.

Abstract: An axial flow type laser oscillator has a laser resonator having a first gas discharge tube (5a) and a second gas discharge tube (5b) connected coaxially, serially and linearly connected (5a, 5b) to form an integral gas discharge tube (5a+5b) and a resonator base (9) containing a gas distribution paths therein for distributing the laser medium gas to both ends of the integral gas discharge tube (5a, 5b) and disposed in substantial parallelism along the laser resonator and holds both ends of said integral gas discharge tube; the resonator base is held at one end by a pin-bearing and the other end by a roller bearing, so that no stress is given to the integral gas discharge tube (5a+5b) even at temperature rise of the laser medium gas.

Abstract: The present invention is directed to a method and apparatus for fabricating a dual beam semiconductor laser, wherein the laser includes first and second semiconductor laser dies respectively affixed to one another while separated by intervening alignment structures. The alignment structures provide accurate placement of the dual laser beams with respect to one another while also assuring thermal isolation of the laser diodes. The fabrication method employs photolithographic techniques to accurately position the alignment structures across an entire semiconductor wafer, thereby assuring accuracy in alignment of the assembled dual beam lasers. As a result, the need for multiple-step alignment operations commonly employed in the production of multiple diode laser devices is eliminated.

Abstract: An apparatus for imaging through scattering materials produces a broadband laser reference beam and a correlated Stokes illumination beam. The broadband reference beam has a preselected Raman pump wavelength and the Stokes illumination beam has a preselected Stokes wavelength. The Stokes illumination beam is transmitted into the scattering material to obtain a Stokes signal beam having a first image carrying component and a first nonimage component. A relative delay is produced between the reference beam and the Stokes signal beam. The delayed reference beam and the delayed Stokes signal beam are polarized.

Abstract: A laser light beam generating apparatus includes at least one light beam source, first and second reflectors, a non-linear optical crystal element and an actuator. The light beam source emits a light beam. The non-linear optical crystal element is provided between the first reflector and the second reflector. A light beam emitted from the light beam source is incident on the non-linear optical crystal element through the first reflector. The actuator actuates at least one of the first and second reflectors along an optical axis of the light beam emitted from the light beam source.

Abstract: A process and apparatus for the modulation and amplification of light beams having at least one input light beam (8) supplied to at least one Fabry-Perot resonator having at least one resonance mode, and defined by two mirrors (M1,M2) and produced by stacking layers on a substrate (4). At least one of the layers form an active medium (6) able to amplify the input light beam by stimulated emission, the wavelength thereof being around the resonance of the resonator and the density of free charge carriers in the active medium being varied in such a way as to make the latter sometimes absorbent and sometimes an amplifying with respect to the input beam and thus obtain at least one output light beam (10) whose intensity is modulated and amplified relative to the input beam. Application to optical telecommunications and to optical interconnections.

Abstract: A semiconductor optical source includes a first laser diode supplied with a signal current pulse and a first bias current for producing an output optical signal pulse in response to the signal current pulse, a first biasing circuit for supplying the first bias current to the first laser diode, a second laser diode supplied with a second bias current for producing an output optical beam in response thereto, a second biasing circuit for supplying the second bias current to the first laser diode; a heat sink for maintaining the first laser diode and the second laser diode at a substantially identical temperature; and a threshold detection circuit for detecting a threshold of laser oscillation of the second laser diode, wherein the threshold detection circuit controls the first biasing circuit such that the first bias current is maintained at a level that is related to the threshold of the second laser diode.

Abstract: A high efficiency, diode pumped laser includes a resonator mirror and an output coupler which define a nearly confocal resonator. Positioned in the resonator is a laser crystal. A diode pump source supplies a pump beam to the laser crystal and produces an output beam. A strong thermal lens transforms a non-confocal resonator to a nearly confocal resonator. The TEMOO mode diameter in the laser crystal may be smaller than the pump beam diameter that is incident on the laser crystal. Output powers greater than about 4 W are achieved, the overall optical efficiency is greater than about 25%, and an optical slope efficiency in a TEMOO mode of greater than 40% is possible.