Joseph P Segre

US Patent:

39633470, Jun 15, 1976

Filed:

May 9, 1974

Appl. No.:

5/468342

Inventors:

Joseph Pipo Segre - Newton Center MA
Norman R. Truscott - Whitinsville MA

Assignee:

American Optical Corporation - Southbridge MA

International Classification:

G01C 308

US Classification:

356 5

Abstract:

A laser rangefinder for clouds, fog, haze and precipitation including an erbium doped laser transmitter, a germanium photodiode monitor and a germanium avalanche photodiode detector. The germanium avalanche photodiode and an amplifier module is positioned at the focus of a parabolic reflector. The transmitter transmits light in a waveband with an optical center at 1. 54 microns and is eye safe. A periscope system aligns the outgoing pulse with the returning light to reduce parallax. To reduce alignment problems when shifts in wavelengths occur, an optical circuit with only reflecting surfaces can be employed. To increase the efficiency of the laser transmitter, the clamps utilized to position the laser rod within the cavity are formed of the same material as the laser rod and the pump light reflector is a second surface mirror with a quartz substrate coated in succession with silver, copper and black paint.

US Patent:

46584013, Apr 14, 1987

Filed:

Mar 15, 1984

Appl. No.:

6/589711

Inventors:

Joseph P. Segre - Newton Center MA
John R. Haavisto - Scituate MA

Assignee:

Northrop Corporation - Los Angeles CA

International Classification:

H01S 310

US Classification:

372 26

Abstract:

Passive ring resonator laser gyro in which the clockwise and counterclockwise beams do not coexist in the resonator. The laser gyro employs thin film technology. In particular, the preferred laser is a gallium aluminum arsenide laser. Light from the laser is phase-modulated by means of a thin film electro-optic modulator comprising a channel waveguide disposed on an electrically active material and flanked by electrodes for modulating the phase of light from the laser. An electro-optic switch is provided for switching light from the laser to inject alternatingly clockwise and counterclockwise beams into the resonator. The resulting gyro is extremely compact and simply implemented into an integrated, thin film package. Because the clockwise and counterclockwise beams do not coexist in the resonator, various beam interaction effects such as beats, backscatter and feedback into the laser are eliminated.