A High-Speed Electro-Optic Phase Compensator for Aero-Optic Applications

Airborne lasers undergo extreme disturbances due to shock waves, turbulent shear layers, and regions of separated flow, caused by the aircraft motion. The net effect of rapidly-varying wavefront turbulence produces degraded beam quality and decreased laser energy-on-target. Unfortunately, progress in adaptive-optic correction has been essentially non-existent because that the required spatial and temporal frequencies are at least an order of magnitude greater than those presently correctable by adaptive-optic systems for the atmospheric-propagation case. In this SBIR program, Crystal Research, Inc. (CRI) proposes to develop a high-speed electro-optic phase compensator for aero-optic aberration corrections. The proposed device is based on high-speed two-dimensional electro-optic phase modulation in a novel crystal that has an electro-optic coefficient 20 times larger than that of conventional electro-optic crystals such as LiNbO3. The proposed electro-optic adaptive system is capable of performing high bandwidth (>100 kHz) wavefront sensing and distortion correction without using any mechanical moving part. In Phase I, we will fully exploit the advantages and feasibility of the proposed concept by designing and fabricating a 2-D EO phase compensator in lieu of a completed adaptive optical system. In Phase II, we will develop and demonstrate a high-speed electro-optic phase compensator for high bandwidth aero-optic applications.