US Government As Represented by the Secretary of the Army

United Technologies Corporation

Robert W Henschke

Robert J Mongeon

Robert J Wayne

The apparatus is part of an optical radar set and comprises a high powered O.sub.2 pulsed transmitter laser which is injection controlled to operate at a fixed frequency offset from a lower powered CO.sub.2 local oscillator laser. A portion of the output of the local oscillator laser is applied to an acousto-optic Bragg cell, together with an RF signal equal to the desired intermediate frequency of the radar set. The upshifted first order output of the Bragg cell is injected into the transmitter laser for stabilization purposes. This results in a stable intermediate frequency for the optical radar set.

Optical radar transceiver control apparatus

A frequency control system for a laser for compensating for thermally-induced laser resonator length changes. The frequency control loop comprises a frequency reference for producing an error signal and electrical means to move a length-controlling transducer in response thereto. The transducer has one of the laser mirrors attached thereto. The effective travel of the transducer is multiplied severalfold by circuitry for sensing when the transducer is running out of extension and in response thereto rapidly moving the transducer and its attached mirror toward its midrange position.

Frequency stabilized laser

This multi-format modulated laser may be programmed to produce a variety of utput waveforms by applying a different one of a plurality of modulating waveforms thereto. The outputs can include continuous waves, both modulated and unmodulated, Q-switched pulses, cavity dumped pulses, shaped pulses and mode locked pulses. The laser is provided with an intracavity electro-optic modulator and may comprise two coupled cavities with a gain cell in one cavity and the modulator in the other cavity.

Programmable multifunction laser

An improved electro-optic moduator device is disclosed which provides strain-free mounting of an electro-optic crystal within a housing assembly and suppression of acousto-optic effects within the crystal. An acoustic matching liquid having an acoustic impedance substantially matching the acoustic impedance of the electro-optic crystal is disposed within the housing enveloping longitudinally the crystal. The acoustic matching liquid effectively suppresses the acousto-optic resonances within the crystal by coupling the acoustic energy out of the crystal into the liquid. The liquid enveloping the crystal also provides a uniform heat conduction path for minimizing thermal gradient variations and the resulting thermally induced strain within the crystal. A zinc oxide suspension in silicone oil is an exemplary acoustic matching liquid for gallium arsenide or cadmium telluride crystals. In one embodiment the acoustic matching liquid has a consistency of a slurry capable of being recirculated through the housing to improve the heat transfer characteristics of the liquid. In a further embodiment an acoustic absorber, disposed in a spaced apart relationship about the crystal, is adapted for absorbing acoustic energy transmitted through the liquid. An elastomeric seal at each end of the crystal provides a liquid-tight seal between the housing and the crystal to maintain the liquid within the housing and provides a soft-mounting structure to minimize thermally and mechanically induced strain within the crystal.

Growing community of inventors

East Hampton, CT, United States of America

Robert W Henschke