Integration of 1024 InGaAsP/InP optoelectronic bistable switches

A photonic parallel memory (PPM), which is an array of 32*32 optoelectronic bistable switches, is discussed. The switch consists of a heterojunction phototransistor (HPT) and a light-emitting diode (LED). Optical positive feedback from LED to HPT is the cause of bistability. The PPM can be written in and read out with 1-kb parallel optical signals. The PPM has been fabricated and memory operation has been demonstrated as expected. Dissipation current for a single switch and the input optical power necessary to turn on the switch were 600 mu A and 20 mu W, respectively. A light pulse with a width of 5 ns was able to turn on the switch, and the product of turn-on power and pulsewidth for the short pulse region was 1.5 pJ.<
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