Abstract: A laser chip is directly disposed on a support member through a mounting arrangement and a support member, the laser chip, and peripheral parts thereof are integrally sealed within a transparent plastic resin. In this structure, without requiring expensive materials and parts, a semiconductor laser apparatus may be manufactured by using the same materials and process as in the ordinary plastic-sealed LED, so that the cost may be reduced significantly.

Abstract: Photoreceptor for frequency-modulated optical signals. The photoreceptor consists of a semiconductor laser (10) fed clearly beyond the threshold (12). The optical signal (20) to be demodulated is injected into the laser. The voltage (V) taken at the terminals of the latter reflects the frequency difference between the frequency of the signal (F1, F2) and the actual frequency (Fo) of the laser.

Abstract: A microlaser is disclosed comprising: a gain medium having one face which is adapted be coupled to a source of optical pumping radiation and having an opposite face; harmonic conversion means having a close face which is located adjacent to and spaced apart from the opposite face of the gain medium and which is coated for high transmission at a fundamental and high reflectivity at a harmonic and having an opposite face which is coated for high transmission at the fundamental and some transmission at said harmonic; and polarization control means, located adjacent to and spaced apart from the opposite face of the harmonic conversion means, for controlling the polarization of the fundamental.

Abstract: Discharge tubes formed of metal fluoride gases are used in apparatus for emitting high frequency laser and fluorescent light. The discharge tubes are resistant to corrosion from halogen-containing gas mixtures subjected to high frequency excitation in the apparatus.

Abstract: An external cavity laser assembly in which the laser chip is within a hermetically sealed package and the external cavity is outside the hermetic package. A collimating lens in a screw threaded mounting is disposed outside the hermetic package, the screw thread permitting focussing. The cavity is turned by rotation and translation of a grating, the position of which is electrically controlled via piezoelectric stacks. Thermal expansion of the stacks is compensated by mounting the grating on a rod of suitable material (e.g., ceramic) which also serves to reduce the cavity length while allowing maximum piezoextension. In a second embodiment the assembly is a tunable laser amplifier, with a grating being driven in a similar manner to provide the tuning.

Abstract: An hybrid laser source has a ring structure including the optical path in a semiconductor amplifier chip (1) and optical fibres (2, 3 and 4). The fibre (2) is rare-earth doped and provides an additional gain medium in the ring, the chip providing its own gain medium. The two gain media are interactive and when the chip input current is modulated the source produces relatively high peak power ultrashort pulses (FIG. 1).

Abstract: The rugate filter comprises a glass film which is deposited on one or both end facets of a diode laser. The glass film has a continuously varying refractive index with thickness, usually in the form of a sine wave or a "windowed" sine wave. Such a film may be deposited by ion-assisted co-deposition techniques in which the concentration of the higher refractive index material is periodically varied according to the period required to produce the desired filter. The glass of which the rugate filter is formed has an average refractive index which does not vary with temperature by more than 10.sup.-6 /.degree.C. By reflecting light at the peak wavelength back into the laser, the laser is caused to emit at the desired wavelength. Since the rugate filter selectively reflects light within a narrow band of the desired wavelength, the laser emits light within a narrow peak on the order of 10 .ANG. or less.

Abstract: Accurate mode partition data from a laser are collected simply and rapidly in accordance with the principles of the invention wherein the laser output is directed to a filter which separates a central longitudinal mode from the side modes. The filter operates to present all side modes in a predetermined wavelength range simultaneously and continuously at the output of the filter. By subsequently comparing the intensity or power in the side modes delivered to the filter output with a predetermined threshold, it is possible to determine the frequency of occurrence and magnitude of mode partition events for side modes in the predetermined wavelength range.

Abstract: A device for source compensating a fiber optic coupler output automatically compensates for changes in light intensity at the output end of the fiber caused by changes in light intensity from the source, beam walking at the input of the fiber and mode changes in the fiber. Laser light enters a frequency doubler and exits as a doubled frequency output which is focused onto the input face of a fiber optic cable by a lens. The lens is selected so that the spot size of the focused light on the face of the fiber is smaller than the diameter of the fiber and that the entry angle of the light cone is within the acceptance angle of the fiber. The fiber is tightly wound into a mode scrambler to provide a uniform intensity distribution of the light exiting the fiber. The light leaving the fiber is collimated and directed to additional optical elements. The collimated beam is directed to a beam splitter which reflects 8% of the incident beam to a calibrated photodiode that is terminated with a transimpedance amplifier.

Abstract: A ring laser is provided with only two reflecting surfaces to define the cavity. A gain medium is located between the reflecting surfaces. At least one optical interface is located within the cavity and is oriented such that the beam will be deflected by refraction to create a ring path. The angle of incidence of the beam with the interface should be less than Brewster's angle and the surface should have an antireflective coating. The interface can be located on the lasant material, on a non-linear optical material or on a passive optical element. Preferably, the device is arranged to achieve unidirectional and single frequency operation. When the ring is used for intracavity second harmonic generation, the resultant output is amplitude stable because of the avoidance of mode beating. The second harmonic radiation is generated unidirectionally increasing useable output.

Abstract: A pulsed source of laser light (10) includes a diffraction grating (20) that splits light received from a laser output mirror (12) into a plurality of paths that lead to respective laser gain cells (14.sub.1, 14.sub.2, . . ., 14.sub.n). The gain cells individually amplify light components of different respective wavelengths and reflect them back to the diffraction grating (20), which reassembles them into a single beam for transmission to the laser output mirror (12). A mode locker (24), preferably in the form of a saturable absorber, locks the output components into equally spaced frequencies so that the sum of the individual continuous components will be a pulsed signal.

Abstract: Sum frequency generating devices are disclosed. The devices include a waveguide having a multilayer structure comprising at least one nonlinear semiconductor material. In a preferred embodiment, each of the layers of the multilayer structure has the same thickness and alternate layers have a first and a second predetermined refractive index. The sum frequency output generated by two contra-propagating beams of fundamental wavelengths within the waveguide is enhanced by the multilayer structure of the waveguide. The sum frequency output is in a direction different from that of the waveguide and contrapropagating fundamental beams.

Abstract: An array of semiconductor laser diodes having parallel waveguide elements, of which each adjacent pair is coupled together by an X-shaped waveguide junction having a connecting waveguide in which lateral modes are formed as a result of merging of the pair of waveguide elements. The waveguide elements diverge again from the connecting waveguide at an angle great enough to ensure that there are high scattering and radiation losses near the point of divergence of the waveguide elements, for the fundamental mode in the connecting waveguide. If an adjacent pair of waveguide elements operate in phase, this excites the fundamental mode in the connecting waveguide, which is effectively suppressed by the losses that occur near the point of divergence from the connecting waveguide. The structure thereby discriminates against connecting waveguide in an in-phase mode, resulting in operation in the 180.degree.

Abstract: Means for coupling an electrooptical device, such as a semiconductor laser, to an optical fiber avoids heat-induced stresses that commonly result from joining methods employing welding, soldering, or catalytic adhesive compositions. In this invention, the electrooptical device and fiber are firmly mounted within separate elements, such as copper tubes, by means of potting compound or the like, and after close end-to-end supported alignment of the device and fiber elements to obtain optimum light coupling, the assemblage is immersed in an electrolytic plating solution. Plating current is then applied and maintained until a sufficiently strong layer of plating metal encompasses the tubular elements and thereby rigidly fixes the alignment of the device and fiber end at its optimum position. Since the plating operation proceeds in a substantially isothermic environment, there is no misaligning stress introduced which would otherwise degrade the coupling efficiency.

Abstract: An optical pulse source for producing short optical pulses comprises first and second optical loops coupled together by a beam splitter so as to define a figure eight optical path in which a light beam propagating toward the beam splitter in one of the first and second loops is split by the beam splitter to form two light beams propagating in opposite directions around the other of the first and second loops. The first loop includes a direction dependent loss element for reducing the intensity of light propagating in a predetermined direction around the first loop, and the second loop includes an element having an intensity dependent nonlinear optical transmission characteristic. One of the first and second loops includes an optical gain medium. Coupling apparatus is also provided for coupling pump light into the loop including the gain medium and for coupling optical pulses out of the source.

Abstract: A passively mode-locked laser suitable for use with homogeneously broadened lasing medium or a lasing medium having a high-power output, long relaxation time or a narrow bandwidth. The laser includes a main cavity in which the lasing medium is disposed and an external cavity including a non-linear element. The non-linear element is selected to induce a non-linear phase shift in a coherent beam from the main cavity. In operation, a portion of a laser beam in the main cavity is coupled to the external cavity and a phase-shifted output from the external cavity is reflected back into the main cavity to provide a narrow pulse, mode-locked output from the laser. In one embodiment the non-linear element of the external cavity is an optical fiber with a mirror disposed adjacent one end of the optical fiber to provide dual propagation of a laser pulse through the fiber. In high-power applications the external cavity mirror is disposed proximate but spaced apart from the optical fiber end.

Abstract: An optical input beam is transmitted through a non-linear medium capable of two-wave mixing gain by photorefractive, Brillouin, Raman, or other non-linear optical mechanism. A psuedo-conjugator retroreflects the input beam which has passed through the medium, back into the medium. The retroreflected beam acts as a seed, which lowers the threshold for producing a self-pumped conjugate reflected beam in the medium by stimulated scattering. The pseudo-conjugator may be a flat array of retroreflecting elements in the form of spheres or corner reflectors. A mosaic pattern of conjugating elements can be phase-locked to yield larger apertures and/or energy scaling, in a master-oscillator, power-amplifier (MOPA), or a four-wave mixer (FWM) configuration. The retroreflected beam can be modulated to temporally encode information onto the conjugate beam, and/or polarized to increase the system efficiency. The input and self-pumped conjugate reflected beams can be used as reference or pump beams in a FWM configuration.

Abstract: A solid-state laser device includes a neodymium laser pump source capable outputting a pump beam of about 1.1 .mu.m wavelength, and a holmium laser being pumped by said 1.1 .mu.m pump beam to generate an output laser beam of about 3 .mu.m wavelength.

Abstract: A nonlinear waveguiding optical converter in a solid state body. The waveguide is provided with compositionally differing region (domains) of dominant electrical polarization in succeeding regions transverse to the path of guided radiation.

Abstract: This invention relates to power laser generators in which it is possible to control the angular direction of output laser beams. The generator according to the present invention is characterized by the fact that it successively comprises on the same optical axis of propagation, a pilot laser beam generator to generate a laser beam wavelength, a controllable deflector, a beam separator, a laser amplifying medium with the wavelength of the pilot beam, and a phase conjugation nonlinear mirror. The laser generator is applicable, in particular, to missile guidance systems or in telemetry systems.