Abstract: An optical resonator has two resonator mirrors disposed opposite one another on a mirror carrier which is divided at an angle relative to a perpendicular plane to the optical axis. Precise adjustment of the mirror spacing is provided by movement along the abutting faces at the dividing plane to match the mirror spacing to the wavelength of the laser emission for frequency tuning.

Abstract: The efficiency of an optically pumped solid state laser is substantially improved with a controlled geometry fluorescent converter between the pump light source and the lasing medium. Fluorescent materials have the capability of absorbing broadband pumping radiation, shifting it in wavelength and re-emitting it in the absorption band of the selected solid state laser medium. Use of angular formations having the converter surface facing the laser medium reduces fluorescent light trapping within the converter due to internal reflection thereby greatly increasing the total light output of the converter and thus the efficiency of the laser.

Abstract: A fiber laser for producing subpicosecond pulses is formed by placing a laser fiber in a resonant cavity, in either a linear or closed loop configuration. The laser fiber is formed of two different types of fibers joined in series, a gain fiber which contains the laser gain medium followed by a pulse shaping fiber which uses the phenomenon of solution pulse shaping to shorten the pulses. An initially formed pulse recirculates many times in the resonator; on each pass the pulse is both amplified and shortened until steady state is reached. The zero dispersion wavelength of the pulse shaping fiber is chosen to be slightly less than the laser wavelength. The fiber is pumped by a continuous source, particularly CW laser diodes. The initial pulse can be formed by a self starting technique produced by selecting the proper length of the laser fiber, or else a mode locker/acousto-optic shutter can be placed in the cavity.

Abstract: An optical transmitter for digitally transmitting data by using NRZ pulses. The transmitter has a laser diode whose operating current consists of a bias current and a modulation current. A photodiode measures the optical performance of the laser diode. Also provided is a regulating device having a multiplier for multiplying the alternating component of a measuring signal transmitted by the photodiode with a signal beat, the latter having the frequency of the bit rate corresponding to the NRZ pulses, with the output signal of the regulating device setting the bias current via a control member to a value which is smaller, by a predetermined amount, than the laser threshold current.

Abstract: Laser apparatus includes a ceramic tube within which is contained a gas and a cylindrical cathode having a plurality of holes therethrough. An anode is located along the axis of the tube. During operation of the apparatus, a large potential difference is applied between the anode and cathode, causing a plurality of electron beams to be formed extensive of the holes. Vapor is emitted from the electron bombarded cylindrical rod and becomes excited, and laser action occurs.

Abstract: A fast axial flow gas laser apparatus comprising an at least essentially closed loop defining a flow path for a laser gas, an arrangement for exciting gas flowing in the loop of the apparatus to cause the gas to lase, and a regenerative compressor for flowing gas through the closed loop along the flow path. The compressor is capable of operating with a pressure ratio sufficient to flow the gas along at least a portion of the loop at a speed at least half the speed of sound in the gas with inlet pressures of only a small fraction of an atmosphere. The uniform discharge pressure of the compressor results in a uniform laser discharge or output. A positive pressure fluid pressure seal prevents lubricant at a bearing support for the impeller shaft of the compressor from moving to the impeller and possibly contaminating the laser gas being compressed thereby and also prevents surrounding air from contaminating the laser gas.

Abstract: Light quantity and temperature settings are applied by a control circuit to a semiconductor laser controller and a temperature controller, respectively. A temperature actuator is controlled by the temperature controller responsive to an output signal from a temperature sensor for equalizing the temperature of a semiconductor laser to the temperature setting. The semiconductor laser is controlled by the semiconductor laser controller responsive to an output signal from a light quantity sensor so that a laser beam will be emitted from the semiconductor laser at the light quantity setting. Mode hoping noise is detected by a mode hopping noise detector or the control circuit in combination with a memory which stores mode hopping noise ranges. In response to a mode hopping noise signal, the control circuit changes at least one of the light quantity and temperature settings.

Abstract: A resonant laser cavity system (10) is provided which is divided into three sections (20, 22 and 24). Sections (20 and 24) include a pair of opposing discharge tube members each including an outer discharge tube (28) and an inner discharge tube (26). On opposing ends of resonant laser cavity system (10) there is provided a mirror mounting mechanism (48) which includes a tubular mount housing (50) upon which is mounted a mirror member (58) positionally located through a plurality of metal clamp members (60) inserted within housing grooves (62) and resiliently coupled to the mirror members (58) through a coil spring (64). The inner discharge tube (26) is formed of a Pyrex composition and the outer discharge tube (28) is formed of an acrylic composition.

Abstract: A highly efficient light emitting semiconductor device which is stable at high speeds and has a low threshold current comprising a first semiconductor layer of a first conductive type; a second semiconductor layer of the second conductive type which is different from the first conductive type; an active layer composed of laminated semiconductor layers of the quantum well structure interposed between the first and second semiconductor layers and having a narrower effective energy band gap than the first and second semiconductor layers and a diffraction grading formed in either one of the first or second semiconductor layers.

Abstract: A laser generator with a catalyst for the laser gas is provided comprising a cavity which communicates with a housing receiving a catalytic cartridge, which communicates also with a laser gas reserve, and which is subjected to the action of the heat released by the laser effect. The cartridge contains, inside a mechanical filter, granules of zeolite on which a manganese dioxide catalyst has been fixed. The generator, whose output power is stabilized, has a long lifespan.

Abstract: A semiconductor laser array device with a waveguide structure comprising waveguides designed such that the widths thereof gradually increase from the center waveguide to the waveguides positioned at both sides of the array portions.

Abstract: A large scan antenna, particularly for embarked use on board a satellite and for operation in the ultrahigh frequency range, of the type formed of a feed and a main fixed secondary reflector, the antenna being readily foldable into a launching configuration with a minimum of component elements, and comprising at least one guide G each formed of a first and a second parabolic secondary reflectors (12, 13) aligned optically along the axis of the wave guide G between the feed (10) and the main reflector (15), said wave guide G being on the one hand variable in length by moving at least one (13) of said secondary reflectors with respect to the other (12) along the axis (14) of the wave guide G, and on the other hand, rotatable about the axis (11) of the feed (10).

Abstract: Apparatus for coupling radiation into a single-mode core of an optical fiber laser has a single-mode core disposed within a relatively large, multimode cladding at a location which is displaced from the center of the cross-section of the cladding. The cladding is surrounded by a further layer to prevent radiation from propagating out of the cladding. In addition, the apparatus preferably has slight bends to enhance the coupling of radiation from the cladding into the single-mode core. A further embodiment has a single-mode fiber laser disposed in a relatively large, multimode, slab cladding which, in turn, is surrounded by another cladding to prevent radiation from propagating out of the large cladding.

Abstract: A small closed loop antenna is formed by a flat metal member formed into a U-shape which also serves as the front, back and top surfaces, or parts thereof, of the housing for a portable communications receiver. Connected to the open (bottom) end of the arms is an isolation network providing an optimum antenna ground and a reactance network which applies a capacitive reactance across the antenna and isolation network so that the conductive member forms an antenna that detects the H-field of the electromagnetic wave to be received. The reactance network is tunable to adjust the antenna for reception at particular frequencies.

Abstract: A modulated laser beam emitted from a semiconductor laser is deflected by a rotating light beam deflector to scan a surface, without using an f.theta. lens. The light intensity of the laser beam is set to a first reference level by a reference signal, and to a second reference level by a corrected-width control signal. Each time the frequency-dividing ratio for a reference clock signal from an oscillator is changed, a digital correction signal is produced. The gain of a D/A converter for converting the correction signal is adjusted by the corrected-width control signal which has been converted to an analog signal. The reference signal which has been converted to an analog signal is modulated by the converted correction signal to generate an analog signal which varies in a step-like manner in proportion to a change in the scanning rate.

Abstract: Chromium doped colquiriite, LiCaAlF.sub.6 :Cr.sup.3+, is useful as a tunable laser crystal that has a high intrinsic slope efficiency, comparable to or exceeding that of alexandrite, the current leading performer of vibronic sideband Cr.sup.3+ lasers. The laser output is tunable from at least 720 nm to 840 nm with a measured slop efficiency of about 60% in a Kr laser pumped laser configuration. The intrinsic slope efficiency (in the limit of large output coupling) may approach the quantum defect limited value of 83%. The high slope efficiency implies that excited state absorption (ESA) is negligible. The potential for efficiency and the tuning range of this material satisfy the requirements for a pump laser for a high density storage medium incorporating Nd.sup.3+ or Tm.sup.3+ for use in a multimegajoule single shot fusion research facility.

Abstract: A laser driver circuit is disclosed for operating an electrical current driven light emitting device or laser. The laser driver circuit is driven from external equipment by a modulated electrical signal and includes a laser biasing network arranged to provide a threshold current to the laser. The current is sufficient to bias the laser to an operating point just below the laser's turn on threshold. First and second transistors connected to the laser form a differential switching amplifier. The differential switching amplifier is disposed to switch drive current provided by a constant current source to the laser. The drive current is sufficient to drive the laser over the threshold set by the laser biasing network. On the application of the modulated electrical signal to the first transistor of the differential switching amplifier the drive current is switched from one side of the differential switching amplifier to the other effectively turning the laser on and off.

Abstract: A semiconductor laser array having a plurality of waveguides at least some of which are directly joined at Y-junctions. The region near the Y-junctions provides a phase boundary condition in which lightwaves propagating in adjacent waveguides are in phase. A combination of strong and weak waveguiding is provided, with strong waveguides that eliminate evanescent coupling from occuring at least in the Y-junction regions, and with weak guides near one or both end facets permitting evanescent coupling. The evanescent coupling between adjacent weak waveguides preserves the in phase relationship that was established in the Y-junction regions, resulting in a diffraction limited single lobe far field output. Alternatively, even without evanescent coupling, the modes can adjust their phases in the weak waveguides, where the propagation constant is less tightly specified by the geometry.

Abstract: Method and device for correlating the spontaneous emission of photons into laser fields. Atoms of a common lasing medium of multiple laser fields are excited into a coherent superposition of upper levels. When photons are emitted into the laser fields, these emissions are coherent or correlated. The method and correlated emission laser of the invention utilize this correlation to quench the spontaneous emission noise inherent in active laser systems.

Abstract: A phase-locked ridge waveguide gas laser includes a body that circumferentially bounds an internal space extending along a central plane and containing a gaseous lasing medium. The gaseous medium is excited at radio frequency with attendant light emission from the gaseous medium. Mirrors are so positioned relative to the body as to provide lasing of the light emission. Respective ridges partition the internal space into a plurality of cylindrical laser resonator cavities each sustaining a guided mode of the lasing light emission. Each of the cavities extends longitudinally of the body and is spaced from an adjacent cavity by a predetermined distance in a width direction of the internal space. The ridges are substantially cusp-shaped and extend into the internal space along a height dimension in respective aligned pairs.