Abstract: A laser oscillation apparatus includes: a laser cavity unit for generating laser light by being provided a voltage and optically amplifying the generated light by means of a pair of mirrors; and a DC power source for supplying the voltage required for generating the laser light to a pair of discharge electrodes of the cavity unit. Each of a cathode and an anode of the DC power source is grounded via a grounding resistor.

Abstract: An asymmetric resonant optical cavity is constructed of an optically transmissive dielectric material having an index of refraction n. The cavity is configured as an oval cross-section of area A, having major and minor axes. An optical input couples an optical signal of wavelength &lgr; into the cavity. An output coupler is positioned in a near-field region of a surface point of the cavity thereby enabling coupling thereinto of optical energy of wavelength &lgr;. The surface point on the cavity is determined by a minimum value of an expression which relates the Sin of the angle of incidence, at an angle ø, to the curvature of the outer surface of the cavity.

Abstract: An interferometric method for providing stability of a laser is enabled by way of utilization of a novel optical interferometric measurement apparatus. The method can enable locking of a laser to a cavity in a bandwidth limited only by propagation delays in the cavity and the tuning behavior of the laser.

Abstract: A semiconductor laser is formed of gallium nitride series compound semiconductor and has a double hetero structure including an MQW (multiple quantum well) active layer held between p-type and n-type AlGaN clad layers. The double hetero structure is held between p-type and n-type contact layers. An InGaN optical absorption layer having an optical absorption coefficient larger than the clad layer which has the same conductivity type as the contact layer and is formed adjacent to the contact layer is formed in at least one of the contact layers and an InAlGaN optical guided mode control layer (layer of small refractive index) having an refractive index smaller than the clad layer is formed on the exterior of the optical absorption layer.

Abstract: In a dye laser system, a porous bed filter is loaded with dye prior to operation of the system. With repeated firings, the dye solution is filtered by the porous bed filter to remove by-products of the laser process. Solute concentration is monitored and dye and additives removed by the filter are replenished by a metering pump. Precise temperature control assures consistent filtering of dye by the filter for more consistent color and energy output. To control the metering pump, the differential output of a two-channel absorption detector is digitized. The digitized signal is loaded into a counter which drives the metering pump. The useful lifetime of the dye solution is enhanced by incorporating pH buffers in the solution.

Abstract: The present invention is directed to a method for adjusting the operating temperature range of a laser module such that it substantially covers or is coextensive with the span in temperatures for the desired application. In accordance with the principles of the invention, it has been found that the laser module's operating temperature range can be readily adjusted by judiciously increasing its thermal resistance so as to elevate, and thereby offset the laser's temperature from its ambient or surrounding temperature. As such, by judiciously impeding the laser module's heat flow, the laser module's operating locking temperature range can be made to be cover the span in temperatures for the desired application. Preferably, washers of a known thermal resistance are employed to increase the laser module's thermal resistance to accordingly impede heat flow from the laser to its surroundings, and thereby offset the laser's temperature.

Abstract: An apparatus and method for protecting at least one component of a light source are provided. The apparatus includes a shield for the component, with this shield having a plurality of locations that are substantially transparent to an emission wave length of the light source. The shield is positioned such that during use of the light source, one of the substantially transparent locations of the shield is disposed between the at least one component of the light source and an object that is to be irradiated. The apparatus also includes a mechanism for advancing the shield upon activation of the light source or an element thereof in order to be able to dispose a different one of the substantially transparent locations of the shield between the at least one component of the light source and an object that is to be irradiated.

Abstract: A laser with a quasi-top-hat pump beam has a modified intensity profile that produces a parabolic temperature gradient. The laser includes a high reflector and an output coupler defining a laser cavity. A gain medium positioned in the laser cavity. A first diode pump source produces a first pump source beam. An intensity profile of the first diode pump source beam is tailored to produce the parabolic temperature gradient across the gain medium.

Abstract: In accordance with the present invention, there is provided a proton beam target for generating gamma rays which are generated therefrom in response to an impinging proton beam. The proton beam target is provided with a 13C gamma reaction layer for generating the gamma rays therefrom. The proton beam target is further provided with a stopping layer for mitigating transmission of the proton beam therethrough. The stopping layer is formed of a refractory metal which is hydrogen soluble for dissolving implanted hydrogen molecules therewithin as a result of the impingement of the proton beam and which is chemically reactive with the 13C gamma reaction layer for chemically bonding therewith.

Abstract: In a laser such as a mode-locked or Q-switched laser, one of the resonator reflectors comprises a switchable Faraday rotator mirror coupled to a switchable magnetic field source. The operation of the laser is therefore controlled by the application of the magnetic field to the Faraday rotator device. When no magnetic field is applied, the device behaves as an isolator and thereby breaks the signal path between the resonator reflectors. When a saturation magnetic field is applied, the reflectors, disposed on opposite sides of the optical gain medium, thereby form a cavity such that lasing will occur. The device may be formed of discrete components or fabricated as an integrated optical device.

Abstract: In a radiographic apparatus having an x-ray tube, a method is provided for continuously conditioning the dielectric fluid in the x-ray tube during operation, thereby extending the service life of the x-ray tube. This is achieved by mounting a filter inside a filter housing, and mounting a replaceable gas reduction cartridge around the filter. The replaceable gas cartridge is filled with a material having a high affinity for the dielectric fluid. When the dielectric fluid enters at the filter outside diameter, the fluid moves radially inward so that the dielectric fluid flows over the high affinity material surfaces. The dielectric fluid then alloys with the high affinity material, thereby continuously conditioning the fluid.

Abstract: An optical pulse source includes a gain-switched semiconductor laser diode. Light from a continuous wave source is opitically coupled into the laser cavity. Light output from the laser cavity passes through an electro-optic amplitude modulator. Synchronized modulating signals are applied to the semiconductor diode and to the amplitude modulator. The source outputs short low-jitter low-pedestal optical pulses and is suitable for use, for example, in a broadband optical network operating at thigh bit rates of 100 Gbit/s or more, or in an optical interconnect.

Abstract: The invention comprises a liquid crystal Fabry-Perot interferometer tuned external cavity semiconductor laser. The laser oscillates single mode at a discrete set of wavelengths defined by the transmission of an intracavity static Fabry-Perot etalon. The liquid crystal Fabry-Perot interferometer has a free spectral range larger than the gain bandwidth of the laser amplifier so that it selects only one transmission wavelength. Its resolution bandwidth is much greater than the free spectral range of the external cavity. The static intracavity etalon's free spectral range is greater than the resolution bandwidth of the liquid crystal Fabry-Perot interferometer. The static etalon maintains a single mode oscillation by providing a filter narrow enough to select only one external cavity mode.

Abstract: A method and apparatus are provided for modulating a laser beam with an information signal. The method includes the steps of modulating a plurality of coherent, optical signals with a respective information signal of the plurality of information signals and directing the modulated optical signals onto a photodiode. The method further includes the steps of detecting the collected signals in the photodiode and refractively synchronizing the laser beam with clock reference signals which allow easy separation of the modulated signal blocks at the receiving end of the fiber optic.

Abstract: A parallel optical signal transmission apparatus suppresses a power source noise, a drift, and timing jitter and drift caused by changes in temperature. The parallel optical signal transmission apparatus has a reference current source 4, which outputs as a direct current reference current a current value that corresponds to a prescribed proportion of a drive current of the laser driver 11, installed on the transmission side and a reference laser diode 121, which emits a standard reference optical signal driven by the direct current reference current, installed on the transmission side. A voltage signal that corresponds to the direct current reference current, which has been converted by the current-voltage conversion circuit 21, is applied as the reference voltage Vref to the comparator 24.

Abstract: An optical filter is formed from at least two grating located in a waveguide region of a semiconductor optical device. Each grating has a multiple peak optical passband. The gratings are spaced apart in the waveguide region and form an optical cavity having a comb-filter characteristic. The gratings may be located in the active region of an optical gain element and in a preferred example are superstructure gratings (SSGs). A number of filters may be joined together in series.

Abstract: Disclosed is a gas laser utilizing radio frequency discharge excitation in the area of sonic or supersonic/subsonic transfer gas flow. The laser uses various types of gases and mixtures of gases as the active medium and provides for RF or UV pre-ionization of the gaseous medium before using radio frequency discharge excitation. The gas is supplied into a receiver, and has downstream therefrom a supersonic nozzle for acceleration of the active gaseous flow to high subsonic or supersonic speeds in order to provide intensive dynamic cooling of the active gas medium. The gas is excited using radio frequency discharge excitation in the critical area of the supersonic nozzle or downstream therefrom. The radio frequency discharge and excitation can also occur within the optical resonator region which is located within the supersonic area of the nozzle. The present invention provides compact, efficient and super-powerful continuous, quasi-continuous and pulse laser systems with wavelengths from 2.03 mkm to 10.

Abstract: A tangential fan, configured to recirculate a lasing gas mixture, has blade members, which are twisted in a substantially helical fashion about the rotation axis of the fan. The circumferential number of blade members can be constant variable between the end flanges. The circumferential position of blade members can shift monotonically or reversibly between the two ends. A tangential fan in accordance with the invention can be made using a conventional method of brazing together individually stamped and formed blade members and hub members. Finishing processes typically include post-machining, electropolishing, and electroless nickel coating.

Abstract: An n-type GaAs buffer layer 702, an n-type AlGaInP cladding layer 703, a multiple quantum well active layer 704 made of AlGaInP and GaInP, a first p-type AlGaInP cladding layer 705a, an optical guide layer 707, a second p-type cladding layer 705b, a p-type GaInP saturable absorption layer 706, and a third p-type AlGaInP cladding layer 707 are sequentially formed on an n-type GaAs substrate 701. In this structure, the volume of the saturable absorption layer is reduced, and the optical guide layer is provided. As the volume of the saturable absorption layer becomes smaller, the more easily the carrier density can be increased, the more easily the saturated state can be attained, and the more remarkable the saturable absorption effect becomes. Thus, a semiconductor laser having stable self-oscillation characteristics and, as a result, having a low relative noise intensity is realized.

Abstract: A solid state laser has an elongate slab of lasing material having a rectangular cross section with the lower face of the slab contacting a slab mount which is of a high thermal conductivity material. Energy to drive the lasing medium is provided by a flash lamp. Upper and lower faces of the slab are polished to an optically smooth finish so that light is able to propagate in a generally axial direction through the slab. Side faces of the slab are polished and then re-roughened to provide a finish with a surface damage zone comparable in depth to the wavelength of the lasing emission. For a lasing wavelength of one micrometer, the depth of surface damage is in the region of one micrometer.