Abstract: A QW diode laser generating orthogonally polarized multiple beams. The device incorporates quantum well active regions capable of, transitions to heavy hole and light hole band edges. The heavy hole transition provides TE-mode gain, while the light hole band provides mostly TM-mode gain. By controlling the compositions and thicknesses of the active regions, both modes can be obtained in a monolithic structure. In addition, the resulting laser polarization will be very sensitive to the threshold carrier density. With an intracavity loss modulator in such a structure, the polarization can also be controlled. Other ways of causing side-by-side lasers to operate, respectively, in their TE or TM modes are also described.

Abstract: An apparatus for and a method of controlling a laser oscillator for use as a laser source in a machining operation or the like is disclosed. In particular, the present invention compensates for a deviation of an actual input/output characteristic of a laser oscillator from a normal (expected) input/output characteristic due to, for example, aging and the like. The present invention approximates the actual input/output characteristic and stores the characteristic as a pattern in a storage device. In response to a detection of the actual laser output and an external intensity command signal, the present invention refers to the input/output characteristic pattern thus approximated and generates an input intensity command signal for controlling the laser oscillator to accurately produce the desired laser beam intensity irrespective of the deviation between the actual input/output characteristic and the normal characteristic.

Abstract: An optically driven interactive Q-switch, i.e., a Q-switch that responds to a short pulse of light, for example, from external light-emitting diodes (LEDs) or diode lasers, is provided for producing an output laser pulse from electronic energy stored in a laser medium. Q-switching is thus achieved on demand by electrically pulsing the light source to produce a pulse of light directed onto a Q-switch medium in the laser cavity. Electronic control of the light pulse from the external source will thus provide not only efficient Q-switching frequency but also independent control of output laser pulse width with a fast rise time for each output laser pulse.

Abstract: An optical isolator comprising first through fourth plate-like birefringent substances. Each plate-like birefringent substance receives and transmits incident light, and has a corresponding optical axis which is inclined with respect to a direction of the incident light. The optical isolator also has first and second magneto-optical materials, each for rotating a plane of polarization of the incident light. The optical axis of the second plate-like birefringent substance is rotated by one of -45.degree. and 135.degree. about a first axis which is perpendicular to a surface of the first plate-like birefringent substance. The optical axis of the third plate-like birefringent substance is rotated by one of 45.degree. and 225.degree. about a second axis which is perpendicular to the surface of the first plate-like birefringent substance. The optical axis of the fourth plate-like birefringent substance is rotated by one of -90.degree. and 90.degree.

Abstract: A semi-conductor laser device constant power output controller including a power input, a laser diode device consisted of a laser diode and a photoelectric diode, a current driver consisted of a first transistor and a second transistor, and an output control consisted of a zener diode and a variable resistor, whereby the electric current to the laser diode is controlled by the second transistor; the electric current to the second transistor is controlled by the first transistor; the photoelectric diode detects the laser beam of the laser diode for feedback reference; the zener diode and the variable resistor control the output power by means of controlling the electric current to the laser diode.

Abstract: A QW diode laser whose polarization can be switched. In one embodiment, the device incorporates a tensile strained quantum well active region, whose thickness is adjusted so that the heavy hole and light hole band edges are of the same energy. Since the heavy hole transition provides TE-mode gain, while the light hole band provides mostly TM-mode gain, the resulting laser polarization will be very sensitive to the threshold carrier density. With an intracavity loss modulator in such a structure, the polarization could be switched. Other switching techniques are also described.

Abstract: A multiple quantum well structure which permits substantially uniform injection of carriers from the outside into respective quantum well layers of the multiple quantum well and a semiconductor device employing such a multiple quantum well structure. A multiple quantum well structure is formed by laminating at least two pairs of quantum well layers each having a thickness substantially equal to the de Broglie's wave-length of electrons and barrier layers of an energy gap greater than that of the quantum well layers, and the multiple quantum well structure is doped with at least one of p-type and n-type impurities in a manner to slope the energy band of the entire multiple quantum well structure so that carriers injected thereinto are distributed uniformly throughout it.

Abstract: There is provided a strained quantum well layer semiconductor laser device that shows an improved temperature dependency of the threshold current and a high frequency performance while maintaining an excellent low threshold current operability. A strained quantum well layer type semiconductor laser device according to the invention comprises a light emitting active layer 14 of a multilayer structure including a quantum well layer 14a and a barrier layer 14c and a pair of light confining layers 13, 15, respectively laid on and under the active layer, the quantum well layer being made of InAs.sub.y P.sub.1-y (0<y.ltoreq.1), the barrier layer and/or the light confining layers being made of In.sub.1-x Ga.sub.x P (0<x.ltoreq.1). Such a device shows an improved temperature dependency of the threshold current and a high frequency performance, while maintaining an excellent low threshold current operability because of the structural features of its active layer.

Abstract: Filtered regenerative feedback is used to modulate a laser or other source of electromagnetic radiation to generate optical pulses whose amplitudes and repetition rates are continuously tunable. The technique is in principle applicable to any source of electromagnetic radiation and is especially effective for semiconductor diode lasers.

Abstract: An intracavity modulated pulsed laser comprising an amplification medium, a pulsed pumping source, a beam modulator, and two mirrors, one totally reflective and one partially reflective for generating at least one laser output burst comprising a plurality of sub-pulses having variably controllable peak powers.

Abstract: A diode-pumped monolithic laser is fabricated from a self-doubling host material co-doped with two ionic species, where one ionic dopant converts pump radiation to continuous radiation at a fundamental frequency and the other dopant acts as a saturable absorber to Q-switch the fundamental radiation which is then frequency doubled to produce pulsed high-intensity green light, the green light being either outputted or further frequency-doubled, into pulsed coherent UV radiation, by means of a non-linear crystal.

Abstract: A slab laser amplifier array includes a plurality of parallel, stacked, laser resonators, with each resonator having a walk-off mode of propagation of laser light from an input side of the resonator to an output side of the resonator where the exiting light diffracts around the resonator mirror. A source of a plurality of phase related, for example co-phasal, light beams supplies phase related light to each input side. The source of phase related light may be a source of one single mode beam followed by a telescope with an aperture having plural stops or a co-phasal array of laser resonators. A laser array of open resonators also has circular concentric electrodes.

Abstract: A monolithic multi-wavelength laser diode array having a composite active region of at least two dissimilar quantum well layers that are partially mixed in at least one of their constituent atomic species in at least one area of the active region. Different areas of the active region are characterized by different emission wavelengths determined by the degree of intermixing. An impurity free interdiffusion, such as vacancy enhanced interdiffusion, is used to provide the intermixing. Each area may have one or more waveguides and distributed Bragg reflector gratings tuned to the emission wavelength of the corresponding area of the active region. Each area or waveguide may also be separately pumped with an individually addressable current injection electrode. The laser output may be coupled into a ferroelectric frequency doubler integrally formed on the array substrate.

Abstract: A semiconductor laser source using a strained active layer of InGaAsN, introduced by the addition of N in the alloy, to obtain semiconductor laser sources that emit TM-polarized light in the wavelength range above 850 nm. The presence of N in the alloy reduces the lattice constant and produces the desired strain effect, i.e., biaxial tension which raises the light hole band (yielding TM polarization) and produces a narrowing of the band gap. Adding In can reduce the strain in the alloy while maintaining the desired band gap and light-hole/heavy-hole ordering.

Abstract: A laser beam dividing apparatus (10) having a first beam splitter (14) with an aperture (16) therein positioned in the path of a laser beam (12) such that a portion of the laser beam (12) passes through the aperture (16) onto a second beam splitter (20) and a portion of the laser beam (12) impinges upon the first beam splitter (14). Both the first beam splitter (14) and the second beam splitter (20) are, optionally, made from a dichroic material such that a green component (24) of the laser beam (12) is reflected therefrom and a yellow component (26) is refracted therethrough. The first beam splitter (14) and the second beam splitter (20) further each have a plurality of facets (22) such that the components (24, 26) are reflected and refracted in a number equaling the number of facets (22).

Abstract: A device includes a transmitter for transmitting a first optical signal towards a target, which incorporates an optical parametric oscillator. A receiver is capable of receiving a second optical signal from said target. The second optical signal is the reflected signal from the first signal. The receiver means comprises an optical parametric amplifier. A wavelength matching device matches the wavelengths produced by the optical parametric oscillator with that received from the optical parametric amplifier. The optical parametric amplifier is typically joined with a laser to form an optical parametric amplifier laser, while the optical parametric oscillator is joined with a laser to form an optical parametric oscillator laser.

Abstract: A turbine-type compressor useful in a gas laser apparatus for flowing gas along a flow path of the laser includes a sealing arrangement about a drive shaft of the compressor for preventing undesirable substances from moving to the compressor impeller along the drive shaft of the compressor and contaminating the laser gas compressed thereby. The sealing arrangement includes a first seal, preferably a vacuum pressure seal, for sealing about the shaft at least during rotation of the shaft, and a second seal comprising a resilient bladder which is selectively expanded and contracted to move into and out of sealing contact with the drive shaft, respectively, for, on one hand, sealing against the shaft when the drive shaft is stationary during pumping down of the laser and, on the other hand, withdrawing the bladder from the shaft when the shaft is rotating. The sealing arrangement is reliable and relatively low cost and uses less gas than a prior art sealing arrangement.

Abstract: A technique has been developed which carefully retro-reflects precisely controlled amounts of light back into a laser system thereby intentionally forcing the laser system components to oscillate in a new resonator called the parasitic oscillator. The parasitic oscillator uses the laser system to provide the gain and an external mirror is used to provide the output coupling of the new resonator. Any change of gain or loss inside the new resonator will directly change the lasing threshold of the parasitic oscillator. This change in threshold can be experimentally measured as a change in the absolute value of reflectivity, provided by the external mirror, necessary to achieve lasing in the parasitic oscillator. Discrepancies between experimental data and a parasitic oscillator model are direct evidence of optical misalignment or component performance problems. Any changes in the optical system can instantly be measured as a change in threshold for the parasitic oscillator.

Abstract: A laser light beam generating apparatus includes at least one light beam source, first and second reflectors, a non-linear optical crystal element and an actuator. The light beam source emits a light beam. The non-linear optical crystal element is provided between the first reflector and the second reflector. A light beam emitted from the light beam source is incident on the non-linear optical crystal element through the first reflector. The actuator actuates at least one of the first and second reflectors along an optical axis of the light beam emitted from the light beam source.

Abstract: Phase-locking means are provided for synchronizing the pulse timing of two (or more) passively mode-locked pulsed lasers. The phase-locking is carried out at a frequency much higher than that of the fundamental repetition rate of the lasers because it results in much higher sensitivity. The signal from the two bandpass filters is applied to a phase detector. A phase-locked loop circuit ("PLL") is employed to generate an error signal which is applied to a piezoelectric transducer ("PZT") attached to a mirror in one of the laser cavities. Corrections in the position of the mirror driven by the error signal help reduce the effects of phase noise in the relative fundamental repetition frequencies of the two lasers so that they are effectively synchronized with one another with a "jitter" of less than 1 ps.