Abstract: The invention provides a semiconductor laser device including an active layer, a semiconductor layer provided with a diffraction grating, an etch-stop layer, a cladding layer provided with a stripe structure, and a current blocking layer arranged at least on a side of said stripe structure, formed in that order on a substrate. In this semiconductor laser device, the etching-stop layer is formed on the semiconductor layer with the diffraction grating, so that damage of the diffraction grating due to etching can be prevented. The invention also provides a distributed Bragg reflection semiconductor laser device, including an active layer, and a current blocking layer having a stripe-shaped window and a diffraction grating formed at least near an end face thereof. This semiconductor laser device can be manufactured with fewer crystal growth processes than conventional semiconductor laser devices.

Abstract: The invention is directed to optical devices comprising a solid-state structured glass substrate having at least one waveguide incorporated therein, particularly waveguides and lasers incorporating such structure. The invention is also directed to methods for modifying such devices and their properties. The waveguides and lasers of the invention provide advantageous high power and increased slope efficiency and find use, for example, in telecommunications applications.

Abstract: Burst and spike characteristics in an excimer laser output in a burst operation are efficiently improved. Xenon gas is added from a compact Xe gas cylinder to gases for excimer laser in a chamber supplied from an Ar/Ne gas cylinder and an Ar/F2/Ne gas cylinder, a ratio of the xenon gas is detected by an Xe gas sensor, and the supply of the xenon gas from the Xe gas cylinder to the chamber is controlled by a gas controller.

Abstract: One-dimensional nanostructures having uniform diameters of less than approximately 200 nm. These inventive nanostructures, which we refer to as “nanowires”, include single-crystalline homostructures as well as heterostructures of at least two single-crystalline materials having different chemical compositions. Because single-crystalline materials are used to form the heterostructure, the resultant heterostructure will be single-crystalline as well. The nanowire heterostructures are generally based on a semiconducting wire wherein the doping and composition are controlled in either the longitudinal or radial directions, or in both directions, to yield a wire that comprises different materials. Examples of resulting nanowire heterostructures include a longitudinal heterostructure nanowire (LOHN) and a coaxial heterostructure nanowire (COHN).

Abstract: The ultrashort fiber laser with a dispersion-managed cavity. The laser is an actively mode-locked sigma laser, typically locked at a repetition rate of 10 GHz, driven by an external frequency source and actively length stabilized, and nearly 10,000 pulses circulate within the laser cavity. A Mach-Zehnder modulator is placed in a loop of polarization-maintaining (PM) fiber. The polarization state of light injected into the non-PM branch evolves in a random manner but is transformed into an orthogonal state by a Faraday mirror; linearly polarized light injected into the branch by a polarizing beamsplitter returns to the beamsplitter also linearly polarized but rotated by 90°. The cavity of the laser is composed of several fibers. The average dispersion Dav is anomalous and is approximately equal to 0.1 ps/(nm·km).

Abstract: An oxide-confined VCSELs having a distributed Bragg reflector with a heavily doped high Al content oxide aperture forming layer disposed between a low Al content first layer and a medium Al content second layer. Between the first layer and the oxide aperture forming layer there may be a thin transition region wherein the Al content changes from a higher Al content to a lower Al content. In some embodiments, the Al concentration from the oxide aperture forming layer to the second layer may occur in a step. The oxide aperture forming layer may be disposed at or near a null or a node of the electric field produced by resonant laser light. During the oxidization of the oxide aperture forming layer, all or some of the other aluminum bearing DBR layers may also become oxidized, but to a substantially lesser degree. The junction between the oxidized portion and un-oxidized portion of these layers is believed to reduce the stability and/or reliability of the device.

Abstract: Long-wavelength VCSELs having top DBR mirrors with multiple levels. The individual levels of the DBR are comprised of different materials. The top DBR mirror level(s) forms a pillar structure and/or are defined by trenches. Top contacts are formed on the top DBR mirror below that mirror's top level. An aperture is formed in one of the DBR layers. An ion implanted region is formed in the top DBR and may extend into the active region and into part of a bottom DBR. The top DBRs are beneficially fabricated by etching parts of upper level(s) down to the lower level(s).

Abstract: A semiconductor laser device having an active region including alternating layers of at least one quantum well layer and a plurality of barrier layers, where two of the plurality of barrier layers are the outermost layers of the alternating layers. Each of the at least one quantum well layer has a compressive strain, and each of the plurality of barrier layers has a tensile strain. In the active region, a strain buffer layer having an intermediate strain is formed between each quantum well layer and each of two barrier layers adjacent to the quantum well layer. Interfacial strain is thus reduced, improving high-output-power characteristics.

Abstract: A distributed feedback (“DFB”) laser featuring improved manufacturing yield and operational characteristics is disclosed. The present DFB laser includes a bottom confinement layer, an active region, and a top confinement layer disposed atop an n-doped substrate. A p-doped first top layer having a first index of refraction is disposed atop the top confinement layer. A grating is defined in the top surface of the first top layer, and a p-doped second top layer is overlaid on the grating. The two laser end facets are antireflectively coated. The grating is anisotropically etched to define a low kappa grating half and a high kappa grating half. Light waves produced in the active region interact with the grating and are biased toward the low kappa grating half that results in the majority of light signals passing through the end facet adjacent the low kappa grating half.

Abstract: A longitudinally pumped laser including one or more active lasing media arranged in an optical laser cavity and at least one pumping device emitting at least one pumping beam toward the at least one active lasing medium. The pumped beam or beams is coupled with the active medium. At least one of the active lasing media includes one or more non-homogeneously doped zones, and the dimension of the doped zones and/or the distribution of the dopants is chosen on the basis of the desired transverse mode of the laser cavity. Such a laser can be used as an amplifier.

Abstract: A wavelength selection element for a tunable laser provides for a single laser structure system that can be made to generate any specific wavelength. The wavelength selection element comprises a transmission component which may include an arrangement of optical components mirrors designed to transmit (e.g. using an array of narrow band pass filters and/or mirrors), and a reflection component, which may include an array of stationary mirrors and MEM (Micro Electro Mechanical) mirrors that are adjustable under local or remote control, to reflect light of a specific wavelength such that the desired wavelength will be filtered from the light coming in from the laser and containing all the wavelength components and selectively reflected back through the semiconductor laser while light of other wavelengths not selected will not be reflected back through the laser.

Abstract: A gallium nitride semiconductor laser device has an active layer (6) made of a nitride semiconductor containing at least indium and gallium between an n-type cladding layer (5) and a p-type cladding layer (9). The active layer (6) is composed of two quantum well layers (14) and a barrier layer (15) interposed between the quantum well layers, and constitutes an oscillating section of the semiconductor laser device. The quantum well layers (14) and the barrier layer (15) have thicknesses of, preferably, 10 nm or less. In this semiconductor laser device, electrons and holes can be uniformly distributed in the two quantum well layers (14). In addition, electrons and holes are effectively injected into the quantum well layers from which electrons and holes have already been disappeared by recombination. Consequently, the semiconductor laser device has an excellent laser oscillation characteristic.

Abstract: When set values of a wavelength and a output level are input, the input set values (of the wavelength and the output level) are collated with data (A), and then, an approximate temperature of a DFB laser is calculated. The calculated approximate temperature is collated with data (B), and then, a output regulation value of the DFB laser is calculated. The input set value (the output level) is added to the power regulation value, and then, an optical output controlling value is calculated. The optical output level of the DFB laser is controlled. The optical output controlling value and the input set value (of the wavelength) are collated with the data (A), and then, a temperature controlling value of the DFB laser is calculated. Consequently, the temperature of the DFB laser is controlled.

Abstract: A tunable semiconductor laser device is presented. The device comprises a laser structure formed by at least two waveguides and an active region located within at least a segment of one of the waveguides; and comprises a tunable spectral filter optically coupled to the laser structure. The tunable spectral filter includes at least two filtering elements, at least one of them being a microring cavity.

Abstract: By tapering the diameter of a flanged barrel laser rod over its length, the maximum trapped path length of a barrel mode can be dramatically reduced, thereby reducing the ability of the trapped spontaneous emission to negatively impact laser performance through amplified spontaneous emission (ASE). Laser rods with polished barrels and flanged end caps have found increasing application in diode array end-pumped laser systems. The polished barrel of the rod serves to confine diode array pump light within the rod. In systems utilizing an end-pumping geometry and such polished barrel laser rods, the pump light that is introduced into one or both ends of the laser rod, is ducted down the length of the rod via the total internal reflections (TIRs) that occur when the light strikes the rod's barrel. A disadvantage of using polished barrel laser rods is that such rods are very susceptible to barrel mode paths that can trap spontaneous emission over long path lengths.

Abstract: A method of making permanent adjustments to the resonant cavity of a laser device in order to match its free spectral range to a specified frequency interval involves monitoring the optical output produced during laser operation or cavity illumination with diagnostic light, determining the free spectral range from the monitored output, and then permanently modifying the effective refractive index of an intracavity waveguide segment of the laser device according to the determined free spectral range obtained from the monitoring step until the desired match is achieved. The permanent index changes can be done in several ways, including illumination of the intracavity segment with an energetic beam (e.g. UV light) to induce a chemical alteration in the waveguide material, such as polymer cross-linking in the waveguide cladding. Evaporative deposition or ablative removal of intracavity waveguide material would also produce the desired permanent modifications.

Abstract: A main laser beam is focused to irradiate a tip of a high-density spouting gas flow formed by heating and then vaporizing a target material by a light beam for preheating making it to the plasma. As the result, the generation of a fast debris in the target material can be suppressed. And a discharge of the fast debris from the target material is also suppressed and extinguished by heating and then vaporizing them by a light beam for transpiration which is emitted at an adjusted time after the generation of the plasma. Thus, the fast debris which still appears in the plasma formed after preheating can be almost perfectly vaporized and extinguished by the light beam for transpiration.

Abstract: A unique method and apparatus for locking on an absolute wavelength of laser light output by a laser package by actively compensating for a change in the temperature of an etalon optical filter is disclosed. Changes in etalon response characteristics due to temperature changes are compensated for by the addition (or subtraction) of an output voltage offset to the voltage control signal sent to the Thermo-Electric Cooler (TEC) from a controller within the laser package. The voltage offset is calculated by monitoring the etalon temperature. The voltage offset value provides for active compensation of changes in the etalon temperature and effectively “readjusts” the output of the laser as if the etalon temperature itself had been readjusted.

Abstract: A gain-coupled DFB laser diode includes a multiple quantum well active layer and a pair of cladding layers sandwiching the multiple quantum well active layer vertically, wherein the multiple quantum well active layer includes a plurality of gain regions aligned in a direction of propagation of a laser beam and repeated periodically, each of the gain regions having a multiple quantum well structure, and a buried layer fills a gap between a pair of adjacent gain regions, wherein the buried layer includes a plurality of high-refractive index layers and a plurality of low-refractive index layers, each of the high-refractive index layers is formed of a first semiconductor material having a first bandgap, while each of the low-refractive index layers is formed of a second semiconductor material having a second, larger bandgap.

Abstract: Photonic integrated circuits (PIC) semiconductor chips are provided with thermal isolation and/or heat dissipation structures between integrated optical components in the PIC chip, particularly integrated active optical components. These structures may also serve as a ground path for electrical circuitry on the PIC chip. An important function is the enhanced thermal isolation from, or dissipation of heat from, between adjacent or neighboring optical components in the PIC so that required spacing between adjacent optical components can be made even less than the thickness of the substrate thereby realizing a more compact optical component array on the monolithic PIC chips.