Abstract: A laser system includes a laser resonator cavity having a resonant axis and a lasing element within the laser resonator cavity. The lasing element emits, under stimulation, light at a wavelength of from about 0.95 to about 1.65 micrometers. There is a flash lamp which optically pumps the lasing element to emit light. A Q-switch crystal lies along the resonant axis within the laser resonator cavity. The Q-switch crystal is formed of a host material having a concentration of Co.sup.2+ ions therein, so as to be a saturable absorber of light of a wavelength of from about 0.95 to about 1.65 micrometers. The Q-switch crystal is preferably Co.sup.2+ -doped yttrium-scandium-gallium garnet or Co.sup.2+ -doped yttrium-aluminum garnet.

Abstract: An active branching unit for interconnecting three cables (two trunk cables and one spur cable) each including optical fibres. In a first interconnection configuration fibres of the trunk cables are connected together via the spur cable. Optical switch means, comprised for example by an erbium doped fibre amplifier (EDFA) (20) and an optical attenuator (21) in series, are disposed between optical fibres of the two trunk cables and are such as to pass telecommunications traffic between the trunk cables when, for example, there is fault in the spur cable and an alternative configuration is required. In this case a pump signal is applied to the EDFA (20) and the loss of the attenuator (21) overcome so that traffic can pass directly between the trunk cables and thus be diverted from the spur cable. This path switching can be achieved automatically.

Abstract: A laser resonant cavity employs a dye sheet Q-switch disposed to receive the output of a laser and a Cr.sup.4+ :YAG Q-switch disposed adjacent the dye sheet Q-switch. Disadvantageous aspects of either Q-switch when used alone are eliminated, resulting in higher output energy and overall efficiency. A new Q-switch employing a dye sheet sandwiched between a pair of Cr.sup.4+ :YAG plates is also disclosed.

Abstract: A blue laser source outputting a beam having a wavelength of approximately 460 nm. A first laser cavity is formed around a Nd:YAG gain medium generating a first light beam having a wavelength of approximately 1064 nm. A second laser cavity, at least partially coextensive with the first laser cavity is formed around a Tm:ZBLAN gain medium generating a second light beam having a wavelength of approximately 810 nm. A non-linear KTP crystal is provided intracavity to both the first and second laser cavities to mix the first light beam and the second light beam and output a third light beam having a wavelength of approximately 460 nm. One of the mirrors forming the first or second laser cavity is coated to output a laser beam having a wavelength of approximately 460 nm.

Abstract: A drive circuit enables high-speed modulation of a laser diode. A transistor is associated with the laser diode. The transistor input is supplied with a constant bias current just below the lasing condition of the diode, and also to one or more switching currents which are shunted to the transistor input through Schottky diodes. This high-speed circuit can be used, for example, for modulating a writing beam in a "laser printer," or in a magnetic driver for a disk writer, or in fiber-optic communication.

Abstract: An optical fiber cable includes a central strength member 11 surrounded by a plurality of optical fiber containing tubes 20, the central strength member and tubes being encircled by a sheath 35. The optical fiber containing tubes have a generally frustum or truncated isosceles triangular shaped profile with the base 22 of the triangular shape having a curvature corresponding to the inside surface of the cable sheath and a top 24 (truncated edge or corner) of the triangle opposite and generally parallel to the base having a curvature corresponding to the outside diameter of the central strength member, the plurality of tubes being positioned adjacent to one another in a pie shape to thereby form a central channel within the cable for the central strength member. The truncated isosceles triangular shape of the tubes have a larger cross-sectional area within the tubes for carrying optical fiber cables. Additionally, the shape of the tubes provides improved resistance to compression of the cable.

Abstract: A device for generating short laser pulses comprises a laser oscillator for generating a first laser pulse, a pulse compression element which retroreflects the first laser pulse by stimulated Brillouin scattering (SBS) as a temporally shortened pulse, a reflection element into which the temporally shortened laser pulse is retroreflected for further temporal shortening of the pulse, and an outcoupling element disposed between the pulse compression element and the reflection element for outcoupling the so shortened laser pulse.

Abstract: A method of using a distributed saturable absorber added to a laser cavity, which by nonlinear wave-mixing of the counterpropagating beams (or spatial hole-burning) promotes a reduction of the linewidth and a single mode operation.

Abstract: A pulsed laser comprises a laser rod (6), and is pumped by diode array (3) selected such that with additional components (7, 9) only a maximum of two longitudinal modes are generated between mirror (1) and output coupler (2). By slow Q-switching Q-switch (9) hoped to get a single longitudinal mode output pulse. However if on the onset of the relaxation pulse mode beating is detected by detector (28), indicating that two longitudinal modes are present, then the optical path length of the resonator is changed by quarter of one wave length, by applying an electrical signal to a pulse length control means (10), such that one of the modes is suppressed prior to the Q-switch being fully opened. The output may be amplified by amplifier arrangement (24).

Abstract: Aimed at preventing a laser light beam profile from fluctuating, and by using the fact that there is a substantially proportional relation between the beam profile and the charging voltage as well as between the beam profile and the composition or the total pressure of the laser gases, an excimer laser device comprises a laser chamber containing laser gases which are excited by initiating an electric discharge in the laser chamber to output laser light, a beam profile detector for detecting a beam profile of the output laser light, and a controller for controlling a electric discharge voltage (excitation intensity) and composition or total pressure of the prescribed types of laser gases in such a way that the beam profile is shaped as desired based on detection results of the beam profile detector.

Abstract: Apparatus, and a related method, for compensating for birefringence introduced in a birefringent medium, such as a solid-state amplifier. The invention includes the combination of a quarter-wave plate, a Faraday rotator and a mirror, which may be a phase conjugation cell. Light passing through the quarter-wave plate is substantially circularly polarized, which is advantageous if the mirror is a phase conjugation cell using stimulated Brillouin scattering (SBS). A second pass through the quarter-wave plate provides a linearly polarized beam of which the polarization angle is orthogonally related to that of the original beam, to facilitate out-coupling of energy from the apparatus. The Faraday rotator effects a total polarization angle rotation of 90.degree. in two passes and helps compensate for birefringence when the beam is passed through the birefringent medium again on the return pass.

Abstract: Disclosed herein is an interferometric-based materials analysis system (10) that employs a novel combination of laser beam shaping and pointing techniques, the use of a low cost, rugged, and compact diode laser (22) as a detection laser, and the use of signal processing techniques that compensate for inherent instabilities and short-term drift in the diode laser. A matched filter processing technique is disclosed for processing interferometrically-obtained data points from a target being analyzed. The matched filter technique is shown to be especially useful for detecting and analyzing Lamb modes within thin targets, such as a silicon wafer undergoing a rapid thermal processing cycle. Also disclosed is a method and apparatus for interferometrically monitoring a target to determine, in accordance with predetermined criteria, an occurrence of a period of time that is optimum for obtaining a data point.

Abstract: A laser oscillator is connected to a power supply device for supplying excitation power to the laser oscillator and a detector is connected to detect the intensity of a laser beam output by the laser oscillator. An apparatus is provided for measuring the resistance value of the detector. A control circuit is operative to provide constant laser power control in response to the detector output under normal conditions but when the output signal of the measuring apparatus indicates a failure, the constant laser output control is changed to the constant power control. The apparatus prevents a constant laser output control from being disabled and workpieces from being defective if the output detector property of a laser changes abruptly.

Abstract: A laser apparatus of the end pumping kind in which an elongated transparent laser element is mounted in spaced relationship within a tubular waveguide which has a highly reflective inner surface. The arrangement is such that, at least along part of the laser element, the optical distances between different points on the surface of the laser element and the inner contour of the waveguide vary.

Abstract: A system comprises a substrate 4, an incident optical waveguide 5 formed on the substrate for receiving a light beam incident thereto, two phase-shift optical waveguides 6 formed on the substrate 4 to be branched from the incident optical waveguide 4 for varying a phase of a transmitted light beam in response to an electric field intensity, an outgoing optical waveguide 7 formed on the substrate 4 to join the phase-shift optical waveguides 6. At least one of the phase-shift optical waveguides 6 has a reversely polarized portion 8 reversely polarized. A light transmission film may be formed at one or a plurality of portions on the phase-shift optical waveguides 6. A buffer layer 14 may be formed on a part on or in the vicinity of the phase-shift optical waveguides 6. A transparent substance film for imparting a stress to one of the phase-shift optical waveguides 6 may be formed on a part or a whole of a portion without the buffer layer 14.

Abstract: A diode pumped, multiaxial mode, intracavity frequency doubled laser resonator has high amplitude stability, meaning that the percent root mean square noise (%RMS) of the doubled output beam power is low. A diode pump source supplies a pump beam to a laser crystal positioned in a resonator cavity and produces a multiaxial mode infrared beam that is incident on a doubling crystal, also positioned in the resonator. A frequency doubled output beam is produced that has an RMS of less than 3%, and in some cases less than 0.2%. The laser is highly efficient, provides high output power, and its output beam is of high spatial quality.

Abstract: A blue and green laser generation method and device adopting the same wherein the method includes the steps of pumping an electron of a first element to a first energy level by employing a first pumping energy to thereby obtain an optoacoustic energy according to a first energy absorption; and pumping an electron of a second element to a second energy level being higher than the first energy level, by employing the optoacoustic energy as a pumping source, to thereby obtain blue and green lasers having a desired wavelength according to a second energy absorption. The device has a core having a predetermined refractive index and which is doped by an element for generating light in a band of a predetermined wavelength by means of energy absorption; and a cladding layer provided around the core and which has a refractive index different from that of the core.

Abstract: A laser pump cavity assembly having a laser rod with a ground outer surface positioned concentrically within an annular jet sleeve which is, in turn, positioned concentrically within an annular outer sleeve. The outer sleeve is coated with a dielectric coating having slits therein arranged to receive focused optical pump radiation from respective laser diode arrays, the pump radiation being transmitted through the outer sleeve and jet sleeve to excite the laser rod. The jet sleeve is positioned to define cooling fluid chambers between the outer sleeve and the jet sleeve, and between the jet sleeve and the laser rod, and is provided with a series of jet holes for directing cooling fluid to impinge perpendicularly on the laser rod. The end faces of the jet sleeve and outer sleeve are further coated with dielectric material to enhance the efficiency of the device. The cooperating end caps which mount the outer sleeve, jet sleeve, and laser rod employ a number of advantageous self-aligning and sealing features.

Abstract: An optical module that includes a plastic package main body and at least one sleeve formed integrally with the package main body is disclosed. The sleeve receives and holds a ferrule provided on an end portion of an optical fiber. The sleeve has a substantially cylindrical shape, and is defined by at least first and second portions. At least the second portion has an inner surface with a plurality of grooves formed therein. The grooves extend in a longitudinal direction of the sleeve and are circumferentially spaced to each other to define protuberant regions therebetween. The inner surface of the second portion and the ferrule have substantially the same diameters, such that the protuberant regions make contact with and support the ferrule.

Abstract: A method of, and apparatus for controlling and compensating for high order frequency chirp in a fast tuned laser. Optical means in the form of chirped Bragg gratings, preferrably in-fiber gratings, are used to compensate for one or more orders of the frequency chirp. Alternatively, or in combination with the optical compensation, an electrical compensation scheme employs integrators in one or more parallel compensation channels to create a composite compensation signal to compensate for specific order nonlinearities. The present invention allows for the generation of shorter bandwidth-limited optical pulses with spectra containing the complete tuning range of the tunable laser.