Abstract

The goal of this research is to build optical connectionist machines (OCM’s) capable of interconnecting many input units to output units via two-dimensional liquid crystal spatial light modulators (SLM’s). Liquid crystals SLM's are chosen because of their low optical absorption and power dissipation, moderate switching speeds, potential for high extinction ratios and resolution. In addition, these materials are birefringent and can easily implement a polarization-based optical associative memory. Previously, we presented results on connecting five input units to five output units [1], and eight input units to eight output units [2] with the OCM. The number of interconnections was limited by the low extinction ratio of the two-dimensional SLM used as the OCM connection matrix (The Radio Shack Pocketvision Model 5 extinction is 5:1). In this paper we present results of using higher contrast computer controlled SEIKO liquid crystal pocket television model LVD.012 and optically addressable ferroelectric liquid crystal SLM’s to hetero-associate pairs of 32 bit long input and output vectors. This association is performed using the least mean square algorithm (LMS), implemented with polarization encoding to represent both positive and negative weights.

© 1989 Optical Society of America