Abstract: A lateral injection VCSEL comprises upper and lower mirrors forming a cavity resonator, an active region disposed in the resonator, high conductivity upper and lower contact layers located on opposite sides of the active region, upper and lower electrodes disposed on the upper and lower contact layers, respectively, and on laterally opposite sides of the upper mirror, and a current guide structure including an apertured high resistivity layer for constraining current to flow in a relatively narrow channel through the active region, characterized in that a portion of the lower contact layer that extends under the top electrode has relatively high resistivity. This feature of our invention serves two purposes. First, it suppresses current flow in parallel paths and, therefore, tends to make the current density distribution in the aperture more favorable for the fundamental mode. Second, it reduces parasitic capacitance.

Abstract: A method and apparatus is provided for stabilizing output beam parameters of a gas discharge laser by maintaining a constituent gas of the laser gas mixture at a predetermined partial pressure using a gas supply unit and a processor. The constituent gas of the laser gas mixture is provided at an initial partial pressure and the constituent gas is subject to depletion within the laser discharge chamber. A parameter such as time, pulse count, driving voltage for maintaining a constant laser beam output energy, pulse shape, pulse duration, pulse stability, beam profile, bandwidth of the laser beam, temporal or spatial coherence, discharge width, or a combination thereof, which varies with a known correspondence to the partial pressure of the constituent gas is monitored. Injections of the constituent gas are performed each to increase the partial pressure by a selected amount in the discharge chamber.

Abstract: According to the present invention there is provided an injection modelocking Ti-sapphire laser system that produces a unidirectional laser oscillation through the application of a ring cavity laser that incorporates no intracavity devices to achieve unidirectional oscillation. An argon-ion or doubled Nd:YVO4 laser preferably serves as the pump laser and a gain-switched diode laser serves as the seed laser. A method for operating such a laser system to produce a unidirectional oscillating is also described.

Abstract: A compound semiconductor light emitting device that confines carriers into an active layer and that has improved light emission efficiency. The device has a first conductive type substrate; an active layer on the first conductive type substrate; a second conductive type sub-layer and a first conductive type sub-layer, in this order from a lower portion to an upper portion of the device, on the first conductive type substrate and at both sides of the active layer; a second conductive type cladding layer on/over the active layer and the first conductive type sub-layer; and a second conductive type contact layer on the second conductive type cladding layer. A p-type diffusion barrier layer is further formed between the n-type sub-layer and the p-type cladding layer.

Abstract: A nitride semiconductor laser device includes an n-type contact layer of n-type GaN and an n-type cladding layer of n-type Al0.35Ga0.65N formed on a substrate of sapphire. On the n-type cladding layer, a multiple quantum well active layer of Al0.2Ga0.8N/Al0.25Ga0.75N, a p-type leak barrier layer of p-type Al0.5Ga0.5N0.975P0.025 and a p-type cladding layer of p-type Al0.4Ga0.6N0.98P0.02 are successively formed. The p-type leak barrier layer has a wider energy gap than the n-type cladding layer, and the p-type leak barrier layer and the p-type cladding layer include phosphorus for making an acceptor level shallow with keeping a wide energy gap.

Abstract: It is an object to provide a semiconductor emission element which can promote radiation while being manufactured easily, and a method of manufacturing the same. In the semiconductor emission element of the invention, a plurality of the laser oscillator are formed on the opposite side of a base of a substrate which is supported by the base. P-sides electrodes are connected to the laser oscillator while extract electrodes having a function of radiation by thickening its thickness are connected to the p-side electrodes. The extract electrodes cover two of the laser oscillators while covering the other two laser oscillators with insulating layers in between. As a result, thermal interference can be terminated while deterioration of the performance of the emitting portion by generation of heat can be suppressed even if the substrate is provided on the base with the opposite side of the emitting portion of the substrate facing the base.

Abstract: A laser system is disclosed. The system comprises laser emitters (102, 104, and 106) forming a laser stack (108). A heater resistor (110) coupled to the laser stack (108) stabilizes the temperature of the laser stack (108). A heat reservoir (112) coupled to the laser stack (108) stores the heat flow from and releases the heat flow to the laser stack (108). A temperature monitor (114) coupled to the laser stack (108) monitors the temperature of the laser stack (108).

Abstract: An edge-emitting laser formed in an opto-electronic chip and having an emission wavelength determined by dielectric interference filter formed on opposing facets between which said laser extends. The two interference filter are each respective Fabry-Perot etalon filters having two interference mirrors sandwiching a resonant dielectric cavity layer so that the filter manifests a flat reflectance spectrum with a deep reflectance notch in its center. The two filters are fabricated with wavelengths of their notches differing by about 2%. The sum of the two filter transmittances represents round-trip cavity loss and has a double-peaked shape with a sharp minimum between the two notch wavelengths. The wavelength of the sum minimum determines the lasing wavelength without the need for a Bragg grating being incorporated within the chip. The invention can be applied to multi-wavelength edge-emitting lasers including multiple laser stripes by applying filters of different wavelengths to the ends of different stripes.

Abstract: A multiwavelength laser includes a phasar portion (2) for providing wavelength accuracy and a DBR portion (14) coupled to the phasar portion (2) for forming a laser cavity (142) with the phasar portion (2).

Abstract: A semiconductor laser device includes a substrate formed of GaAs. A lower electrode is formed on an underside of this substrate. Formed, on a top surface of the substrate, are a lower cladding layer, an active layer and a first upper cladding layer. A ridge including a second upper cladding layer is formed on the first upper cladding layer. A current restricting layer is formed in a manner of clamping this ridge from both sides. A contact layer is formed on the ridge and current restricting layer. A third upper cladding layer is formed between the ridge and current restricting layer and the contact layer.

Abstract: A system and method for providing a wavelength locker is disclosed. In one aspect, the method and system include providing a reflector, a first filter, and a second filter. The reflector is for receiving an optical signal, transmitting a first portion of the optical signal, and reflecting a second portion of the optical signal. The first filter is for receiving the first portion and transmitting a third portion of the optical signal. The first filter includes a first axis and is capable of being tuned by rotation around the first axis to transmit the third portion including a particular wavelength. The second filter is for receiving the third portion and transmitting a fourth portion of the optical signal. The second filter includes a second axis substantially perpendicular to the first axis and is capable of being tuned by rotation around the second axis to transmit the fourth portion including the particular wavelength.

Abstract: At least part of the waveguide of a laser, the waveguide including a first cladding layer, an active layer, and a second cladding layer of a second conductivity type, and, for a ridge type laser, a ridge in the second cladding layer, has a width such that light leaks from the side walls of the waveguide. A case encloses the side walls of the waveguide and a fluid having a refractive index is sealed in the case in contact with the side walls of the waveguide. A characteristic of the laser can be adjusted easily. Therefore a laser having a uniform characteristic can be provided at a low cost. This laser is useful as a light source for wavelength multiplex transmission used for optical transmission, of a main line system, such as a submarine cable.

Abstract: An optical fiber mode-locked laser is disclosed. The laser comprises a gain medium doped optical fiber to achieve a population inversion between high and low energy levels by a pump light source and to oscillate optical waves in sequence, a cholesteric liquid crystal circular polarization mirror to transmit the waves from the pump light source and to be operated as a circular polarization reflection mirror for the oscillated optical waves from the gain medium doped optical fiber, a polarization controller to control the polarization state of the proceeding light which is oscillated from the gain medium doped optical fiber, a dispersion shifted fiber to give a non-linear effect to the proceeding light through the polarization controller, and an optical fiber laser output mirror which forms a resonator by putting out some portion of the proceeding light by transmission and reflecting the other portion of the light.

Abstract: A laser structure may be used to fabricate a plastic laser and achieve electrically-driven lasing action. The structure comprises an LED, a waveguide laser, and a substrate disposed between them. The substrate has a first and a second side. Light emitted from the LED is received by the substrate at the first side and concentrated as it is guided with the body of the substrate to the second side, where it is received by the laser. Concentration of the light across the substrate improves the efficiency of the device and leads to lower threshold powers.

Abstract: A semiconductor laser with a rewritable wavelength stabilizer which comprises a laser mirror made of a grating written into a photorefractive material, in which the oscillation wavelength of the laser diode is determined by the period of the grating. This allows the refractive index of the grating to be changed by illuminating the photorefractive material after cooling thereof to a temperature at which most of the doped impurities form DX centers. The grating can be erased by heating the photorefractive material to a temperature at which most DX centers are ionized, which erases the grating. Thereafter the photorefractive material is cooled again to a temperature at which most impurities become DX centers, and a new grating can be written in the photorefractive material. The wavelength of the semiconductor laser can be changed repeatedly by erasing and rewriting the grating therein.

Abstract: A pulsed laser system includes a laser pump, a laser rod, a reflector interposed between the laser pump and the laser rod, through which energy from the laser pump enters the laser rod, an output reflector through which energy is emitted from the laser rod, a switch interposed between the laser rod and the output reflector, and a control device. The switch, when closed, causes energy to be stored in the laser rod and, when opened, allows energy to be emitted from the laser rod during an emission period. The control device allows a primary laser pulse emitted from the laser rod during the emission period to impinge on a workpiece and blocks from the workpiece secondary laser emission occurring during the emission period after emission of the primary pulse. The pulsed laser system is operated over a range of repetition rates, so as to cause laser energy to be emitted during a plurality of emission periods at each repetition rate.

Abstract: In the pattern of a selective growth mask for directly forming an active layer, open stripes for growing recombination layers to be inserted into a current blocking are formed in addition to an open stripe for growing the active layer. By this mask pattern, the position and band gap of the recombination layers are controlled. Whereby, at an arbitrary position in the vicinity of the active layer, recombination layers having an arbitrary band gap can be batch formed together with the active layer. Thus, a semiconductor laser element with an excellent high-temperature high-output characteristic can be fabricated with good uniformity and reproducibility.

Abstract: A high power laser optical amplifier system for material processing comprises multiple stage fiber amplifiers with rejection of propagating ASE buildup in and between the amplifier stages as well as elimination of SBS noise providing output powers in the range of about 10 &mgr;J to about 100 &mgr;J or more. The system is driven with a time varying drive signal from a modulated semiconductor laser signal source to produce an optical output allowing modification of the material while controlling its thermal sensitivity by varying pulse shapes or pulse widths supplied at a desire repetition rate via modulation of a semiconductor laser signal source to the system to precisely control the applied power application of the beam relative to the thermal sensitivity of the material to be processed. The high power fiber amplifier system has particular utility in high power applications requiring process treatment of surfaces, such as polymeric, organic, ceramic and metal surfaces, e.g.

Abstract: A solid state laser comprises a cavity resonator in the form of a generally cylindrical body and, located within the resonator, an active region which generates lasing light when suitably pumped. The resonator has a relatively high effective refractive index (n>2 and typically n>3) is sufficiently deformed from circularity so as to support at least one librational mode (e.g., a V-shaped or a bow-tie mode, the latter being presently preferred for generating relatively high power, directional outputs). Specifically described is a Group III-V compound semiconductor, quantum cascade (QC), micro-cylinder laser in which the resonator has a flattened quadrupolar deformation from circularity. This laser exhibits both a highly directional output emission and a three-order of magnitude increase in optical output power compared to conventional semiconductor micro-cylinder QC lasers having circularly symmetric resonators.

Abstract: An intersubband semiconductor light source comprises a core region that includes a unipolar, radiative transition (RT) region having upper and lower energy levels, an injector-only (I) region disposed on one side of the RT region, and a reflector/extractor-only (R/E) region disposed on the other side of the RT region. The I region has a first miniband of energy levels aligned so as to inject electrons into the upper energy level, and the R/E region has a second miniband of energy levels aligned so as to extract electrons from the lower energy level. The R/E region also has a minigap aligned so as to inhibit the extraction of electrons from the upper level. A suitable voltage applied across the core region is effective to cause the RT region to generate light at a wavelength determined by the energy difference between the upper and lower energy levels. Low voltage operation at less than 3 V is described.