Abstract: A laser system having a high power output and a large volume gaseous discharge has a plurality of electrodes at each end of a channel to establish a plurality of discharges and a housing arranged to provide a continuous recirculating lasing gas flow through the channel. An ejector connected to a main circulating pump is fixed to discharge into the recirculating lasing gas flow adjacent the channel to mix lasing gas streams and cause diffusion of the gas and thereby provide a uniform plasma flow in the channel. In one embodiment, magnets are arranged to surround the channel to eliminate thermal instabilities, if they arise, and to further homogenize the lasing gas streams and insure their uniformity.
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: A device for the amplification of optical signals comprises a light-sensitive medium receiving a modulated signal optic wave and a pump wave, in which the response time of the light-sensitive medium is substantially greater than the mean period for the modulation of the signal wave. The device can be applied to optical transmission in telecommunications.
December 22, 1987
Date of Patent:
July 11, 1989
Jean-Pierre Huignard, Brigitte Loiseaux, Gauthier H. de Monchenault, Claude Puech
Abstract: A laser comprising an RF matching unit having an RF power input and an RF power output, an optical cavity including electrode apparatus extending along the optical cavity, receiving the RF power output and defining a discharge gap having a gaseous lasing medium disposed therein, the RF power output being operative to produce a population inversion in the gaseous lasing medium, and an arrangement for providing direct fluid cooling contact with the electrode apparatus generally along its entire extent.
December 21, 1987
Date of Patent:
July 11, 1989
Alumor Lasers Ltd., Yissum-Research Development Company of the Hebrew University of Jerusalem
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: An electrically self-oscillating radio frequency-excited gas laser. The discharge section of the laser resonates at a desired radio frequency as a result of incorporating the discharge section into the feedback loop of a power oscillator circuit. This laser structure facilitates initial plasma breakdown and adapts its frequency depending upon whether the gas in the discharge section has broken down. When the laser plasma tube is integrated with the oscillator, the laser is also somewhat smaller compared to gas lasers having conventional crystal-controlled amplifier chains.
Abstract: A drooping elimination device for a semiconductor laser is provided in a laser beam recording apparatus comprising a laser operation control circuit for producing a light emission level instructing signal corresponding to an image signal, and controlling a drive current for the semiconductor laser based on the light emission level instructing signal to modulate the intensity of a laser beam emitted by the semiconductor laser, and an optical output stabilizing circuit for detecting the intensity of the laser beam, and feeding a feedback signal corresponding to the detected intensity to the light emission level instructing signal.
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: A simple, compact, and rugged laser comprises a solid transparent housing with two cavities. A laser medium is embedded in one cavity and a pump lamp in the other. By choosing for the housing and lamp envelope materials having thermal expansion coefficient similar to that of the laser medium, high power operation is feasible. An optional reflecting coating on the exterior of the housing enhances efficiency. A filter coating on the lamp envelope eliminates unwanted components of lamp radiation.
June 16, 1987
Date of Patent:
May 30, 1989
Robert C. Morris, Norman G. Schroeder, Jerry W. Kuper, Michael L. Shand, Joseph J. Barrett
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: A transparent photo detector device according to an aspect of the present invention comprises: a transparent insulator substrate; a plurality of light sensor elements dispersively disposed on a main surface of the substrate, said sensor element including a transparent front electrode, a semiconductor layer for photo electric function and an opaque back electrode formed in that order on the main surface of the substrate, said semiconductor layer being neither protracting from nor retracting into between said front and back electrodes; and a transparent wire pattern formed on the main surface of the substrate for electrically connecting the plurality of sensor elements.
Abstract: An optical fiber for transmission of high intensity infrared radiation comprising a core of a silver or thallium halide crystal, a first infrared transmitting layer 5 .mu.m thick of lead or barium fluoride and an overlying highly conductive metal film whereby both waveguide and radiation modes leaking out of the core are attenuated.
Abstract: An apparatus for controlling a laser device comprises means for outputting at least two levels of reference voltage from which a reference voltage is selected in accordance with the consecutive excited time of a laser rod which is excited to emit laser light by a light source. The light source is turned on under a charged voltage of capacitance th level of which is controlled in comparison with the reference voltage so that the laser light is precisely controlled in its energy density and radiation angle to avoid the influence of thermal lens effect of the laser element. This is accomplished by selecting an appropriate level of the reference voltage from the two or more levels of reference voltage.
Abstract: An access panel employing an expanded metal panel having its peripheral edges seated in framing strips of U-shaped cross section is assembled by the use of a pair of opposed corner plates of a relatively soft, non-metallic material formed with recesses which enclosingly receive and orient the end portions of framing strips at each corner of the panel. Fastening members, such as rivets or nut and bolt units, fixedly clamp the opposed corner plates against the opposite sides of the panel-framing strip assembly.
Abstract: An optical cable of the present invention comprises: an optical fiber sensor, the optical fiber sensor having an optical fiber having an external circumferential wall portion and a flexible coating film covering the external circumferential wall portion; and a tube member with a good flexibility, the tube member having an axis and an internal circumferential wall portion and receiving the optical fiber sensor along the axis such that the coating film faces the internal circumferential wall portion of the tube member, the tube member having a portion where the axis is bent; wherein fluid is sealed in between the coating film and the internal circumferential wall portion of the tube member with its pressure being changeable.
Abstract: A semiconductor laser device including at least one of a laser active layer formed of a super lattice and an optical guide layer formed of another super lattice is disclosed in which part of at least one of the super lattices is converted into a mixed crystal by the impurity induced disordering based upon one of impurity diffusion and impurity ion implantation, to divide the super lattice into a first region formed of the mixed crystal and a second region having the super lattice structure, the width of the second region in directions perpendicular to the lengthwise direction of a laser cavity varies along the above lengthwise direction, and the width of a laser excitation region is smaller than the mean value of the width of the second region, to generate laser oscillation having a single transverse mode and a multi longitudinal mode. Thus, the semiconductor laser device emits a laser beam which is small in astigmatism and low in optical feedback noise.
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.
June 15, 1987
Date of Patent:
April 25, 1989
English Electric Valve Company Limited
Arthur Maitland, Clifford R. Weatherup, Ian A. Strudwick
Abstract: A bore tube free end support structure is positioned between an outer cylindrical envelope and an inner capillary bore tube of a laser. The support structure has outer and inner pluralities of circumferentially-spaced spring fingers integrally connected to and extending from respective outer and inner peripheries of a solid annular disc-like middle portion thereof. The outer spring fingers are alternately bent in opposite directions. The outer end of each outer spring finger defines a pair of pointed corners adapted to dig into the inside surface of the glass outer envelope of the laser, so as to anchor the support structure firmly in position with respect thereto. The inner spring fingers all extend in the same direction and each is arcuate-shaped in a longitudinal section therethrough.
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 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.