Abstract: The location of gases that are not visible to the unaided human eye can be determined using tuned light sources that spectroscopically probe the gases and cameras that can provide images corresponding to the absorption of the gases. The present invention is a light source for a backscatter absorption gas imaging (BAGI) system, and a light source incorporating the light source, that can be used to remotely detect and produce images of “invisible” gases. The inventive light source has a light producing element, an optical amplifier, and an optical parametric oscillator to generate wavelength tunable light in the IR. By using a multi-mode light source and an amplifier that operates using 915 nm pump sources, the power consumption of the light source is reduced to a level that can be operated by batteries for long periods of time. In addition, the light source is tunable over the absorption bands of many hydrocarbons, making it useful for detecting hazardous gases.

Abstract: An optical circuit including a semiconductor substrate; an optical waveguide formed in or on the substrate; and an optical detector formed in or on the semiconductor substrate, wherein the optical detector is aligned with the optical waveguide so as to receive an optical signal from the optical waveguide during operation, and wherein the optical detector has: a first electrode; a second electrode; and an intermediate layer between the first and second electrodes, the intermediate layer being made of a semiconductor material characterized by a conduction band, a valence band, and deep level energy states introduced between the conduction and valence bands.

Abstract: An external-cavity laser, suitable for producing a coherent and highly-polarized optical emission, particularly at communication wavelengths, is enabled by a novel wavelength selective element based on a waveguide technology that supports a long-range plasmons polariton mode. These external-cavity lasers leverage the inherent properties of the novel wavelength selective elements, which are materials agnostic, providing easier means for tunability, laser stability, and low cost of fabrication, high output power and a highly polarized output. Tunable versions are also disclosed.

Abstract: Optoelectronic devices, such as optical transmitters and optical amplifiers, are provided. The optoelectronic devices are suitable for use in connection with optical communications systems, and related components and devices, such as may be used in the transmission, reception and processing of data and other information. The optoelectronic devices are implemented as various types of semiconductors. The form, structure, properties and functionality of a particular optoelectronic semiconductor device are determined with reference to the application(s) in connection with which the optoelectronic device is to be employed.

Abstract: High frequency laser diode (LD) and electro-absorption modulator (EAM) integrated circuit drivers using a cascaded output switch architecture that increases the output current and voltage edge speed and reduces the peaking and ringing of the output waveform, thus improving the deterministic jitter performance. Also disclosed is a method and apparatus that provides a modulation current dependence of both turn-on and turn-off driving currents that lead to an optimal compromise between the edge speed and output overshoot for a wide range of modulation currents. A PTAT temperature dependence of both voltage swing and current level in the predriver assures a low variation of the overshoot and rise/fall time over a wide temperature range. Using the cascaded output switch architecture provides an easy way of on-chip summation of the modulation and bias currents. Biasing the cascode device with a supply and modulation current dependent base voltage provides an optimum headroom output switch.

Abstract: A solid laser apparatus has either a combination of a lowpass filter and a highpass filter or a bandpass filter provided in its output control circuit for increasing the gain and adjusting the phase of a signal in the vicinity of the relaxation oscillating frequency. Also, a solid laser apparatus has the phase shift circuit provided in its output control circuit for advancing the phase of a signal in the vicinity of the relaxation oscillating frequency thereof. Moreover, a solid laser apparatus has a pseudo notch filter, which is arranged for the gain to have a local minimum at the relaxation oscillating frequency of the solid laser apparatus, provided in the output control circuit so that the peak of the gain transmission characteristic of the nonlinear optical device or of a combination of the nonlinear optical device and the microchip laser crystal is offset.

Abstract: A method for fabricating a buried semiconductor laser device including the steps of: forming a mesa structure including a bottom cladding layer, an active layer and a top cladding layer overlying an n-type semiconductor substrate; and forming a current confinement structure by growing a p-type current blocking layer and an n-type current blocking layer on each side surface of the mesa structure and on a skirt portion extending from the each side surface, the p-type current blocking layer being fabricated by using a raw material gas containing a group III element gas and a group V element gas at a molar ratio between 60 and 350 inclusive. In this method, the semiconductor laser device including the current confinement structure with the specified leakage current path width can be fabricated with the excellent reproducibility.

Abstract: A laser oscillation apparatus includes a wavelength change unit for driving a wavelength selection element in a band-narrowing module and changing the oscillation wavelength of a laser beam to a target value, and an oscillation history memory for storing the oscillation state of the laser beam as an oscillation history. The wavelength change unit drives the wavelength selection element on the basis of the oscillation history and changes the oscillation wavelength of the laser beam to the target value.

Abstract: A tuneable laser has a gain section bounded at one end by a first reflector in the form of a distributed Bragg reflector adapted to produce a comb of reflective peaks and on the other end by a second Bragg reflector, the second Bragg reflector adapted to reflect at a plurality of wavelengths and being capable of being varied selectively through discrete segments so that one or more segments of the Bragg reflector can be tuned to a lower wavelength to reflect with a segment reflecting at that lower wavelength to enhance the reflectivity at that lower wavelength.

Abstract: RF excited gas laser consists of a laser tube having external surfaces; a power supply compartment having elongated external fins and a pair of endplates on its opposite ends and wherein laser tube is placed between and is flexibly attached to the endplates; a sheet-metal cover mounted to the endplates and to power supply compartment and forming a laser assembly and having at least one pair of intake openings and at least one pair of exhaust openings for the cooling air to flow through the laser assembly by entering the laser assembly through the intake openings and flowing over power supply external fins and over laser tube external surfaces and then exiting through the exhaust openings. Present invention is characterized by lower cost and more efficient forced air cooling laser tube and RF power supply.

Abstract: A semiconductor laser element has the following structure. In the clad layer, a difference in a light radiation loss between the basic horizontal-lateral mode and the 1st-order horizontal-lateral mode is 10 cm?1 or more. The refractive index of the clad layer is below an effective index against light in the basic horizontal-lateral mode, and the refractive index of the clad layer is equal to or more than an effective index against light in the 1st-order horizontal-lateral mode. The upper clad layer is provided only above a portion of the active layer, and thus is at least included in the ridge-stripe structure. This structure inhibits the I-L characteristic from suffering kink and realizes oscillations in the basic horizontal-lateral mode until output power reaches as high as 60–100 mW, in a peak output power of the semiconductor laser element at the time of a pulse current operation.

Abstract: An apparatus and a method for generating an optical carrier is disclosed. The apparatus includes: a light source generating a pump light; a SBS generator for stimulated Brillouin scattering the pump light to generate a stokes light from the light source; an attenuator for controlling an amplitude of the pump light from the light source to generate an amplitude controlled pump light; and a detector for heterodyne beating the stokes light and the amplitude controlled pump light to generate an optical carrier.

Abstract: A solid-state laser (10) has a laser resonator (20) with output ports (22) at both ends to provide two separate laser micromachining beams (42). A set of wavelength converters (26) can be employed to convert the laser machining beams (42) to harmonic wavelength outputs, thus reducing the risk of damage to the wavelength converters and enabling higher total average harmonic power to be generated from a single laser. The laser machining beams (42) can be different to perform different laser operations independently or can be adapted to have substantially identical parameters to permit simultaneous parallel high-quality laser operations on substantially identical workpieces (54), or the laser machining beams (42) can be combined to provide a single laser system output (42e). The two laser machining beams (42) can be further split or multiplexed to suit particular applications.

Abstract: A laser diode includes a substrate having a lattice constant of GaAs or between GaAs and GaP, a first cladding layer of AlGaInP formed on the substrate, an active layer of GaInAsP formed on the first cladding layer, an etching stopper layer of GaInP formed on the active layer, a pair of current-blocking regions of AlGaInP formed on the etching stopper layer so as to define a strip region therebetween, an optical waveguide layer of AlGaInP formed on the pair of current-blocking regions so as to cover the etching stopper layer in the stripe region, and a second cladding layer of AlGaInP formed on the optical waveguide layer, wherein the current-blocking regions having an Al content substantially identical with an Al content of the second cladding layer.

Abstract: An integrated circuit lithography technique called spectral engineering by Applicants, for bandwidth control of an electric discharge laser. In a preferred process, a computer model is used to model lithographic parameters to determine a desired laser spectrum needed to produce a desired lithographic result. A fast responding tuning mechanism is then used to adjust center wavelength of laser pulses in a burst of pulses to achieve an integrated spectrum for the burst of pulses approximating the desired laser spectrum. The laser beam bandwidth is controlled to produce an effective beam spectrum having at least two spectral peaks in order to produce improved pattern resolution in photo resist film. Line narrowing equipment is provided having at least one piezoelectric drive and a fast bandwidth detection control system having a time response of less than about 2.0 millisecond.

Abstract: A system for tuning the wavelength of a beam from a tunable laser. A tunable etalon assembly includes a Fabry-Perot etalon with paired reflectors to filter the laser beam. The tunable etalon also includes a thermal unit to thermally adjust the separation of the paired responsive to an etalon tuning signal. A photodetector receives the laser beam after filtering the etalon and generates a detected signal based on intensity. A controller generates the etalon tuning signal, and receives the detected signal and generates a laser tuning signal based on it. Optionally, additional Fabry-Perot etalons, photodetectors, and one or more beamsplitters permit extending wavelength range and determining relative wavelength difference with a beam from a second laser.

Abstract: A wide-stripe diode-laser includes a lower cladding region, a lower waveguide region, an active region, an upper waveguide region, and an upper cladding region all comprising semiconductor layers epitaxially grown on a semiconductor substrate. An elongated rectangular electrode on the upper cladding layer defines a stripe or pumped section. Adjacent the electrode is an unpumped section in which at least the quantum-well layer has been treated to cause the active region to be disordered. In this unpumped section, at least one area of the area is etched to a depth equal to or less than the thickness of the cladding region. The etched area provides a diverging lens effect in the waveguide region. The diverging lens effect expands the fundamental mode of the laser in the stripe to a width sufficient to improve single mode performance.

Abstract: A semiconductor laser chip unit includes an electrode pattern and a ground electrode; a semiconductor laser chip which is die-bonded to the ground electrode and outputs a laser beam according to a high-frequency signal transmitted from the electrode pattern and the ground electrode, and a collimator lens for collimating the laser beam from the semiconductor laser chip. The semiconductor laser chip and the collimator lens are so positioned that the laser beam output from the semiconductor laser chip is made incident on a surface of the collimator lens at a position inside of the focal point of the collimator lens, and the unit is integrated in a non-conductive heat sink so as to form a unit.

Abstract: Crystal housing apparatus for adjustably positioning cooperating non-linear optical crystals in a laser beam generating system, includes a housing (50) with entry (60) and exit (62) windows for respective laser beams, respective holder means (72, 74, 76) to retain respective crystals within the housing in optical alignment with the windows, and means (86) mounting the respective holder means for individual fine rotational adjustment of the crystals about respective axes. Individual temperature control elements (120) are mounted in association with the respective holder means for controlling the temperature of the respective crystals and means (110, 114) is provided for effecting the fine rotational adjustment of the crystals.

Abstract: A semiconductor laser includes a multilayer semiconductor laser heterostructure including at least one active layer of a II-VI semiconductor material and is optically pumped by one or more indium gallium nitride (InGaN) diode-lasers. Group II elements in the II-VI semiconductor material are zinc, cadmium, magnesium, beryllium, strontium, and barium. Group VI elements in the II-VI semiconductor material are Sulfur, Selenium, and Tellurium. In one example of the laser an edge emitting heterostructure includes two active layers of zinc cadmium selenide, two waveguide layers of zinc magnesium sulfoselenide, and two cladding layers, also of zinc magnesium sulfoselenide. Proportions of elements in the cladding layer material and the waveguide layer material are selected such that the waveguide layer material has a higher bandgap than the material of the waveguide layers.