Infrared nonlinear neurons using the field shielding effect in CdTe

Abstract

We report on a novel IR neuron device that utilizes the field shielding effect in CdTe:In, wherein optical activation beams create an intensity dependent space-charge field. The induced electrooptic birefringence or index change is used in a neuron-type configuration to demonstrate a high sensitivity nonlinear saturated response with an absorption loss of </=1.0 dB. We have also demonstrated operation with synchronous microsecond pulses as well as the availability of both excitatory and inhibitory inputs. Additional interesting features include the possibility of a broadband (0.9-1.4-microm) response to incoherent inputs and a configuration for a bidirectional neuron which can be used in backpropagating error learning networks.