Richard A Craig

US Patent:

49437828, Jul 24, 1990

Filed:

Mar 21, 1988

Appl. No.:

7/170957

Inventors:

Ronald R. Stephens - Westlake Village CA
Richard R. Craig - Los Angeles CA
Huan W. Yen - Westlake CA
Richard C. Lind - Woodland Hills CA

Assignee:

Hughes Aircraft Company - Los Angeles CA

International Classification:

H01S 398

US Classification:

330 43

Abstract:

A four-pass conjugate optical amplifier system and method are disclosed in which a linear polarized optical beam is directed by various optical elements through four passes of a power amplifier, preferably a diode laser structure. The beam is phase conjugated at the optical midpoint between the second and third amplifying passes, and is controlled by the optical elements so that its polarization is substantially the same during the first and second passes, and again substantially the same during the third and fourth amplifying passes. This is accomplished by a reflective coating on the back facet of the diode laser structure, with a non-reciprocal polarization rotation element located in the beam path between the phase conjugate mirror and power amplifier. For considerably enhanced power amplification, the beam may be divided into an array of subbeams, which are individually amplified by four passes through respective power amplifiers. The subbeams are processed by the optical system so that they recombine into a single coherent output beam after full amplification.

US Patent:

48036960, Feb 7, 1989

Filed:

Jun 30, 1987

Appl. No.:

7/067893

Inventors:

David M. Pepper - Malibu CA
Richard R. Craig - Los Angeles CA

Assignee:

Hughes Aircraft Company - Los Angeles CA

International Classification:

H01S 308

US Classification:

372 95

Abstract:

A laser is disclosed which uses a curved spatial grating in either its reflective or output regions, or both, or distributed throughout the laser resonator, to produce an unstable optical reflection pattern which fills the resonating cavity more efficiently than in prior devices. Various combinations of different grating curvatures are disclosed. The invention is particularly adapted to semiconductor lasers.