Trw Limited

Gerald W Holleman

Hagop Injeyan

Michael G Wickham

Jacqueline G Berg

Donald Glen Heflinger

Stephen John Brosnan

James M Zamel

Charles W Clendening, Jr

Leonard J Marabella

A photonic crystal fiber (,) is provided for a laser/amplifier system including a guiding structure comprising a geometric array of axial passages (,) formed along the length of the fiber (,). More particularly, the guiding structure includes a central silica rod (,) which is doped with a rare earth element for providing optical gain to the laser/amplifier. A plurality of second silica rods (,) are disposed circumferentially about the central rod (,). Each of the second rods (,) includes an axial passage (,) formed therethrough along the length of the fiber (,). A reflective coating (,) is deposited on an outboard surface of the array of rods (,) to confine pumped light (,) therein. The pumped light (,) may be injected into the fiber (,) from the side by focusing it through small holes (,) in the reflective coating (,) or by reflecting it off transverse Bragg gratings (,) written into a fiber pigtail (,) coupled to the fiber (,). The mode field diameter of the fiber (,) is controlled by properly selecting the diameter and spacing of the passages (,) in the second rods (,).

Photonic crystal fiber lasers and amplifiers for high power

An apparatus for optically pumping an optical fiber from the side comprising a laser for supplying a beam of pump light, and an optical fiber having a longitudinal surface disposed to the beam, a grating formed in the flat surface for diffracting the beam at a predetermined angle, and an outer clad layer proximate the grating and so as to establish at least one propagating mode characterized by an angle, the predetermined angle being matched to such angle.

Apparatus for optically pumping an optical fiber from the side

A technique for operating a diode pumped solid state laser in a continuous-wave (cw) mode using diodes blocks (12) that are individually operated in a pulsed mode. For some high power laser applications, it is desirable to provide for operation in pulsed and cw modes, but pump diodes are typically designed for efficient operation in only one of these modes. The invention includes a controller (20) that pulses the individual diode blocks (12) on and off, but not necessarily in unison. For a pulsed mode of operation, the diodes (12) in an array are pulsed either at the same time, or sub-arrays are pulsed in a temporally interleaved manner for a higher effective pulse repetition rate. For the cw mode of operation, the diodes (12) are pulsed sequentially in sub-arrays (A-E), such that at least one sub-array is always energized and the complete array appears to be providing continuous pumping energy. In one embodiment, the sub-arrays (A-E) are columns of the array. In another embodiment, the sub-arrays (12') are each associated with a different solid-state gain medium (10'), the gain media being optically coupled in a single laser.

Diode array providing either a pulsed or a CW mode of operation of a

A method and apparatus for controlling the form and timing of pulses emitted by a high-power solid-state laser, without the need for complex feedback circuits. The width and peak intensity of relaxation pulses emitted by the laser are controlled by use of an acousto-optic modulator (14) installed in the laser cavity, to lock the relaxation pulses to the frequency of radio-frequency (rf) control signals applied to the modulator. The number and average rate at which the pulses are emitted from the laser are independently controlled by varying the duty cycle of diodes (20) used to pump solid-state amplifiers (18) installed in the laser cavity. Short pump pulses can be selected to deliver only a few relaxation pulses from the laser, or longer pump pulses can be selected to deliver large numbers of relaxation pulses during each pump pulse. Feedback control of the modulator (14) is not needed because the pumping rate is uniform for the duration of each pump pulse and, therefore, the peak intensities of relaxation pulses emitted by the laser are relatively uniform. Accordingly, the solid-state laser can be conveniently controlled to produce a desired average power output while maintaining good beam quality.

Laser pulse profile control by modulating relaxation oscillations

A dual-wavelength laser emitter is provided for emitting a dual-wavelength laser beam. The laser emitter includes a first laser beam source for generating a first laser beam having a first frequency and a second laser beam source for generating a second laser beam having a second frequency. A beam splitter is included for combining portions of the first and second laser beams to form a dual-wavelength laser beam. The dual-wavelength laser beam is then amplified via an amplifier. A stimulated Brillouin scattering cell may be included to phase conjugate the dual-wavelength laser beam to improve the quality of the output beam. A frequency-doubling crystal may further be included for doubling the frequency of the dual-wavelength laser beam. The dual-wavelength laser emitter then emits a laser output beam as a function of the frequencies and amplitudes of the first and second laser beams.

Growing community of inventors

Manhattan Beach, CA, United States of America

Gerald W Holleman