Incorporation of Coherent Image Amplification Into AN Optical Processor Utilizing Feedback, with Applications.

To further improve the performance of a coherent optical processor with optical feedback, the incorporation of gain has been investigated. The processor has been previously applied to the high speed solution of partial differential equations in two dimensions. By offsetting losses within the feedback system, enhanced performance has been obtained and some new applications realized. A coherent optical image amplification system suitable for incorporation into the optical computer was developed. The technique utilizes a two stage injection-locked dye laser/amplifier. This system was used to successfully demonstrate amplification of a two dimensional image illuminated by the 6328 A radiation of He-Ne. The amplifier maintains spectral bandwidth, relative phase, and propagation direction, over a one-quarter (mu)sec pulse duration. The system was subsequently improved through the development of an expanded grating-tuned injection -locked folded ring dye laser for signal preamplification. A comparison was drawn between the ring design and the previous linear cavity. Improvements include enhanced locking efficiency and increased peak power output. To ensure temporal compatability of the dye image amplifier and the processor, the transient response of the optical feedback system was investigated over the time period from the moment light first enters the system to when steady state operation is established. Light at several discrete points in the two dimensional output was measured with high-speed detectors to display time evolution of the solutions. The optical processor together with the image amplification system was used to demonstrate increased accuracy of solution to partial differential equations. In addition, a new method of applying the optical processor to problems of matrix inversion utilizing optical gain was investigated. Comparative experimental results are presented.