Abstract: A kink suppression technique is disclosed in which optical characteristics of a distributed feedback laser diode's resonant cavity are controlled to preferentially prevent establishment of higher order lateral modes. This results in increased kink powers and thus the useful power range of the device. Specifically, an optical layer, preferably silicon or titanium, is disposed along the optical axis, on the etched upper cladding layer, and on both sides of the ridge.

Abstract: A waveguide (10) is provided having a two-dimensional optical wavelength Bragg grating (20) embedded within a semiconductor laser medium (16). More particularly, the waveguide (10) includes an active region (16) sandwiched between n-doped and p-doped cladding layers (14, 22). The two-dimensional Bragg grating (20) is formed in the active region (16). Upper and lower electrodes (24, 26) are defined on opposite sides of the cladding layers (14, 22) to complete the waveguide structure (10). The two-dimensional grating (20) provides simultaneous frequency selective feedback for mode control in both the longitudinal and lateral directions.

Abstract: A monolithic long-wavelength vertical optical cavity device built up along a vertical direction. The device, when designed as a surface emitting laser, has a bottom Distributed Bragg Reflector (DBR), an active region consisting of active bulk medium or quantum wells, a current confinement layer next to the active layer, and a top DBR. The bottom DBR and the active region are lattice matched to the lattice defining material, while the top DBR is lattice relaxed. The design achieves high reflectivity, low absorption and diffraction loss. The design also ensures low production cost due to low precision requirement and wafer size production. The device can be used as a light detector when the active region is replaced by a spacer or a optical filter.

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 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 laser system for the generation of an ultra-short light pulse—with a laser resonator which contains at least one active solid-state oscillator element, preferably a thin disk of a laser-active crystal with a high amplification bandwidth, particularly of a “quasi-three-level” system such as Yb:YAG—comprises at least one respective arrangement for phasecoupling of the laser modes and for dispersion compensation. For industrial applications,in order to be able to emit ultra-short pulses with very high average powers in a power-scalable fashion while being constructed optimally simply and inexpensively, the arrangement for phase coupling is constructed as a passive, non-linear element, and a prismless arrangement for dispersion compensation is provided.

Abstract: A laser system for operation at elevated temperatures with minimal cooling requirements. The laser system comprises a laser media having first and second optical ends and an input port. The laser system further comprises at least one high-temperature laser diode which optically communicates with the laser media and is operative to generate a source beam of light which is transmitted into the input port of the laser media. Optically communicating with the first optical end of the laser media is at least one reflector, while optically communicating with the second optical end of the laser media is at least one optical coupler. The laser media, the reflector and the optical coupler are configured to form a laser resonator operative to generate a laser beam which is transmitted through the optical coupler.

Abstract: A gallium nitride-based compound semiconductor laser has a double-heterojunction structure, in which an active layer is sandwiched between cladding layers, on a sapphire substrate. A GaN current blocking layer having a striped opening portion is formed on the p-cladding layer. A p-GaN buried layer and a contact layer through which a current is injected into the opening portion of the current blocking layer and which are larger in area than the opening portion are formed. The active layer has a multiple quantum well structure constituted by a cyclic structure formed by cyclically stacking two types of InGaAlN layers which have different band gaps and are 10 nm or less thick.

Abstract: Several methods are used in novel ways with newly identified and viable parameters to decrease the peak transition energies of the pseudomorphic InGaAs/GaAs heterostructures. These techniques, taken separately or in combination, suffice to permit operation of light emitting devices at wavelengths of 1.3 &mgr;m or greater of light-emitting electro-optic devices. These methods or techniques, by example, include: (1) utilizing new superlattice structures having high In concentrations in the active region, (2) utilizing strain compensation to increase the usable layer thickness for quantum wells with appropriately high In concentrations, (3) utilizing appropriately small amounts of nitrogen (N) in the pseudomorphic InGaAsN/GaAs laser structure, and (4) use of nominal (111) oriented substrates to increase the usable layer thickness for quantum wells with appropriately high In concentrations.

Abstract: In a semiconductor laser element including a multilayered structure being formed of a plurality of semiconductor layers made of a plurality of group III-V compounds, and having at least a pair of cleaved end surfaces as a pair of light resonator surfaces, a first reflectance control layer, made of an oxygen gettering material which has a function of gettering oxygen, is formed on at least one of the pair of light resonator surfaces, and a second reflectance control layer made of a nitride of a group III material is formed on the first reflectance control layer.

Abstract: A light source controller having a look-up table that indicates the amount of current to be provided to a light source to maintain wavelength and spectrum stability at various temperatures. Further, the light source may have a heater/cooler to maintain a constant temperature of the light source. The controller provides the appropriate current to the light source from the time of turn-on until it achieves thermal equilibrium, to provide an output having a relatively constant wavelength during the warm-up period and during changes of ambient temperature about the light source. The light source may have a heater and/or cooler to maintain a constant ambient temperature, so that the light source controller can provide a more refined control of the light source output wavelength and spectrum. The light source controller may be particularly used for a light source in a fiber optic gyroscope.

Abstract: A tunable pulsed narrow bandwidth light source and a method of operating a light source are provided. The light source includes a pump laser, first and second non-linear optical crystals, a tunable filter, and light pulse directing optics.

Abstract: It is an object of the present invention to provide a semiconductor light emitting device capable of securing, in use of an optical information processing or an optical communication system, a low threshold and high efficiency operation as well as a high output characteristic. An active layer structure having a flatness and an interface acuteness of a quantum well structure improved by introducing a multi-period super lattice structure between a substrate for crystal growth and a light emitting layer area further to on a misoriented substrate sued to enhance a homogeneity of a semiconductor crystal. Further, a carrier confinement and a light confinement can be enhanced by providing a margin for design of the quantum well structure.

Abstract: A top surface emitting vertical cavity laser with enhanced power handling capacity. The laser provides a patterned top electrode for uniformly injecting applied current to the active area. The diameter of the electrode relative to the vertical distance between it and the active layer is reduced by patterning. The result is an improved laser with significant power output.

Abstract: A source of intense coherent high-frequency electromagnetic radiation such as soft x-rays. A circularly polarized incident beam of coherent radiation is directed at a frequency multiplication medium that includes constituents of approximate Cn symmetry, oriented so that the symmetry axes of the constituents are parallel to the incident beam. The interaction of the incident beam and the constituents of the medium produces higher harmonics of the incident frequency, up into the x-ray band. If the Cn symmetry of the medium constituents is exact then the harmonic frequencies are multiples ln±l of the frequency of the incident beam, where l is an integer. If the Cn symmetry is only approximate, then the harmonics are centered around these multiples. Suitable medium constituents include dipolar molecules of C5v symmetry and circular rings of nanoparticles.

Abstract: A multistage optical amplifier pumping system with built-in redundant reliability for lightwave communication system provides plural levels of redundancy. A first level of redundancy deals with redundancy in the form of plural primary laser diode sources for pumping a single fiber laser pump source. A second level of redundancy deals with redundancy of a plurality of fiber laser pump sources for pumping a plurality of serially connected injection signal fiber amplifiers forming the multistage amplifier system. If one of fiber pump sources should fail, increased pumping power is available from the remaining fiber pump sources via their respectively connected amplifier stages. A third level of redundancy deals with redundancy in the employment of multiple single mode laser emitters on the same chip or bar sufficiently segmented and/or electrical isolated so as not to interfere with operation of or cause failure to adjacent or neighboring emitters on the same chip or bar.

Abstract: Apparatus and methods for monitoring the wavelength of laser radiation and that provide a temperature-corrected error signal responsive to the deviation of the wavelength of the laser radiation from a nominal wavelength is disclosed. The apparatus includes a least one optical filter for filtering the laser radiation according to at least one spectral filter function to produce filtered laser radiation and at least one optical detector for detecting the filtered laser radiation to produce a first detected signal. The apparatus also includes a temperature sensor for sensing temperature characteristic of at least the optical filter and processing circuitry for providing a temperature-corrected output signal responsive to the deviation of the wavelength of the laser radiation from the nominal wavelength.

Abstract: An array type laser diode includes an active layer, a cathode electrode, and bonding electrodes. The active layer is formed in a substrate into a stripe shape to serve as an emission portion. The cathode electrode is formed on a mounting surface of the substrate into a stripe shape to be close to the active layer. The bonding electrodes are formed on the mounting surface of the substrate to be physically separated from the drive electrode.

Abstract: Semiconductor laser with a tunable gain spectrum. Said laser comprises an active zone having at least one active quantum well (AQW), which emits a laser radiation during the introduction of carriers into the active zone and at least one collection quantum well (CQW1, CQW2) on either side of the active well, for collecting and confining part of the carriers introduced. Means for distributing carriers in the collection wells are provided for creating a space charge field for modifying, during the emission of radiation and by an electrooptical effect, the gain spectrum of said active well. Application to optical telecommunications.

Abstract: The screening of edge-emitting laser diode bars in a production line is permitted by fabricating the source electrodes of each diode in the bar in two parts spaced apart to form a window aligned with the lasing cavity of the diode. Such windows have been made in failed devices to determine the cause of failure. Here, the windows are formed in a wafer stage of fabrication for later separation into laser bars or individual laser diodes. All wafers, all laser bars and all laser diodes are fabricated with windows thus permitting automatic screening during fabrication rather than opening a window to examine only failed devices as is the case in the prior art.