Abstract: The present invention relates to a solid solution semiconductor laser element material which can be used for a laser element which oscillates within an inflated region of wavelength range of 0.4-8 .mu.m, can vary wavelength and can be operable in the vicinity of room temperature. The present invention more particularly relates to a material which can be used for a laser element having a lattice matching type double hetero-structure or lattice matching type quantum well structure.

Abstract: A process for controlling the preconduction current of a laser diode that operates in conjunction with a monitor diode in a control circuit with operational amplifiers, comprising signal processing filters, an electric supply unit such as, e.g., a power source, and a zero crossing detector, where the laser diode (5a) is driven by a linear current ramp signal provided by the supply unit, that the output signal (16) of the monitor diode (15) is differentiated three times, and that, when a zero crossing of the triple-differentiated monitor diode output signal (16) is detected, an optimum current of the current ramp signal is retained by the action of the zero passage detector.

Abstract: A semiconductor interference mirror principally comprising a large number of pairs (36) of semiconductor layers (38,40) having different dielectric constants and having optical thicknesses equal to one-quarter of the wavelength of light to be reflected. For example, the two semiconductors are InP and InGaAsP for reflecting 1.55-.mu.m light. However, every 10 to 15 periods in the mirror, the InP layer (44) is grown more slowly to a thickness that is an odd multiple of its usual quarter-wavelength thickness. Because indium is so mobile and binary composition is well defined, the binary InP layer replanarizes the growth, thus assuring a planar mirror. The faster growth rate for the majority of the mirror allows the mirror to be grown in a shorter time, thus reducing process variations.

Abstract: A tunable external cavity semiconductor laser is provided with a semiconductor laser diode, a diffraction grating and a movable mirror. The diode laser is positioned to illuminate a diffraction grating and a movable mirror is positioned to reflect a selected wavelength back into the cavity. The mirror is mounted on a pivot so positioned to provide simultaneous rotation and linear translation. The pivot point is selected so as to provide an internal cavity length which is exactly an integral number of half wavelengths at three different wavelengths and an exceptionally close (within 1/1000 of one wavelength) match at all other wavelengths within the tuning range. Significantly, the pivot point calculation takes into account the effect of the dispersion of the laser and other optical elements in the system on the cavity length.

Abstract: A high power electromagnetic pulse driver for generating sub-microsecond rise time pulses having energy contents greater than 1 joule includes an electromagnetic pulse compressor and an electromagnetic shock line for compressing the leading edges of those pulses. The shock line may use non-linear materials whose permeability or permittivity vary greatly with varying field strength. One material whose permeability varies by a useful amount is metglass, an amorphous alloy of silicon and iron. The high power electromagnetic pulse driver may drive gas discharge lasers.

Abstract: An electric field absorption light modulation unit includes a light emission device for emitting light and a modulation device for varying a light transmittance thereof of light applied by the light emission device so as to provide the light as a result of modifying thereof. A driving signal generating unit coupled with the electric field absorption light modulation unit generates a driving signal to be applied to the modulation device from an input information signal by making the modulation device vary the light transmittance thereof, and the driving signal generating unit provides the driving signal so that the driving signal in a fluctuation range in which an undesirable level fluctuation may be present, corresponds to a constant working range of the modulation device, the light transmittance thereof staying at a constant value in the constant working range.

Abstract: A continuous wave(CW) activator ion doped fiber laser is presented which lases at a normally self-terminating laser transition at a slope efficiency greater than that achieved by a self-terminating fiber laser. Two laser transitions, one corresponding to a self-terminating laser transition and the other to a transition out of the lower level of the self-terminating transition, are simultaneously stimulated in the activator ion doped fiber. Through simultaneous lasing of the two wavelengths corresponding to these transitions, the lower level of the self-terminating transition is sufficiently depopulated so that CW operation is achieved.

Abstract: The invention relates to a pumping lamp for use with lasers comprising a porous substrate loaded with a component capable of emitting light upon interaction of the component with exciting radiation and a source of exciting radiation. Preferably, the pumping lamp comprises a source of exciting radiation, such as an electron beam, and an aerogel or xerogel substrate loaded with a component capable of interacting with the exciting radiation, e.g., a phosphor, to produce light, e.g., visible light, of a suitable band width and of a sufficient intensity to generate a laser beam from a laser material.

Abstract: Apparatus (20) for increasing the length of a laser pulse to reduce its peak power without substantial loss in the average power of the pulse. The apparatus (20) uses a White cell (10) having a plurality of optical delay paths (18a-18d) of successively increasing number of passes between the field mirror (13) and the objective mirrors (11 and 12). A pulse (26) from a laser (27) travels through a multi-leg reflective path (28) between a beam splitter (21) and a totally reflective mirror (24) to the laser output (37). The laser pulse (26) is also simultaneously injected through the beam splitter (21) to the input mirrors (14a-14d) of the optical delay paths (18a-18d). The pulses from the output mirrors (16a-16d) of the optical delay paths (18a-18d) go simultaneously to the laser output (37) and to the input mirrors ( 14b-14d) of the longer optical delay paths. The beam splitter (21) is 50% reflective and 50% transmissive to provide equal attenuation of all of the pulses at the laser output (37).

Abstract: In this invention, a semiconductor device designed for use as an optical amplifier is provided with three sections; an input section, a middle section and an output section. A continuous optical waveguide extends through the input section, the middle section and the output section and the three sections are electrically isolated from each other. More specifically, a semiconductor laser amplifier is electrically split into three separate sections by implanting ions of, for example, hydrogen, helium or fluorine into the areas of the semiconductor amplifier which are between the middle section and the two end sections. The ion implantation provides a high degree of electrical isolation between the various sections, but it does not alter the continuity of the optical waveguide which passes through the three sections.

Abstract: A transverse-type laser assembly is disclosed herein. This assembly defines a laser cavity containing a vapor or gaseous substance which lases when subjected to specific electrical discharge excitation between a pair of spaced-apart electrodes located within the cavity in order to produce a source of light. An arrangement located entirely outside the laser cavity is provided for inducing a voltage across the electrodes within the cavity sufficient to provide the necessary electrical discharge excitation to cause a vapor substance between the electrodes to lase.

Abstract: The disclosed tunable (wavelength and/or focal length) laser typically is a surface emitting laser that comprises a multilayer structure that comprises the lower Bragg reflector and the active region. A layer of electro-optic material (typically liquid crystal material) is in contact with the top surface of the multilayer structure, and means are provided for applying a voltage across the layer of electro-optic material. In one exemplary embodiment, the layer is inside the laser cavity, making the laser wavelength tunable. In another exemplary embodiment the laser is a Z-laser that focuses the output radiation, with the multilayer structure comprising also the upper Bragg reflector. In this embodiment the layer of electro-optic material is outside the laser cavity, and the laser has tunable focal length. A still further embodiment is both wavelength- and focal length-tunable. Lasers according to the invention can be advantageously used in a variety of applications, e.g.

Abstract: The disclosed article comprises a semiconductor laser (typically a multi-segment DBR laser) and feedback means for controlling the laser wavelength. The wavelength reference element in the feedback means advantageously is an optical fiber comprising an in-line refractive index grating. Such gratings frequently have a transmission spectrum that exhibits subsidiary lobes, in addition to the desired main lobe, potentially compromising the "cold-start" ability of prior art systems. This and other drawbacks of prior art systems exemplarily are overcome by apparatus that comprises a feedback loop that comprises means for causing a current I.sub.B to flow to the "Bragg" section of a multi-segment DBR laser such that wavelength of the laser output is a function of I.sub.B, and that further comprises means for changing the temperature of the laser in response to a change in the wavelength of the laser. Use of a wavelength reference element that has a relatively wide primary minimum facilitates cold starting.

Abstract: A mode locked fiber ring laser comprising an optical fiber, an output mirror, a partially reflective/partially transmissive mirror and a unidirectional attenuator. The unidirectional attenuator comprises, in sequence, a first linear polarizer, with its polarization axes at 0.degree., a first quarter wave plate with its axis at .theta..degree., a non-reciprocal rotator for rotating the polarization of incident light by .gamma..degree., a second quarter wave plate with its axis accented at (.theta.+.gamma.+90).degree. and a second linear polarizer with its polarization axis at .gamma..degree.. The parameters .theta. and .gamma. are selected to provide a desired relative phase shift between counter-propagating beams in the fiber and to attenuate the beam in one of the directions so as to create an additive pulse mode-locked (APM) type passive mode locking system.

Abstract: A nonlinear optical device having a yttrium-aluminum-garnet or yttrium-lithium-fluoride laser rod for producing radiation of a fundamental wavelength, a first mirror located in front of the laser rod along the longitudinal axis of the laser rod reflective of the radiation of the fundamental wavelength but transmissive of radiation of a desired harmonic wavelength, a second mirror located to the rear of the laser rod along the longitudinal axis of the laser rod reflective of radiation of the fundamental wavelength, a phase matched crystal harmonic wavelength generator mounted on a movable platform driven by a motor arranged between the front mirror and the laser rod responsive to radiation of the fundamental wavelength for generating radiation of the desired harmonic wavelength, an output sensor arranged in front of the first mirror for generating a signal indicative of the output power of the laser rod, a beamsplitter for directing a portion of the laser rod output power to the output sensor and a computer fo

Abstract: Apparatus is disclosed for generating two streams of optical pulse signals having less than 100 femtoseconds of jitter. A Ti:sapphire laser that is self mode locked by using self focusing in the gain medium and a weak HITCI intercavity dye jet for starting generates a first stream of substantially 100 femtosecond pulses. This first stream of optical pulses is split into two parts, one of which is used as a desired stream of optical pulses and the other of which is used to pump an HITCI dye laser synchronously to generate a second desired stream of optical pulses. The pulses of the second stream from the dye laser have durations of about 140 femtoseconds and less than 100 femtoseconds of jitter relative to the pulses of the first stream.