Optimising the readout process in integrated phase-change photonic memory and computing devices

Abstract

In integrated phase-change photonic memory and computing devices, the basic operation involves using light guided into an integrated waveguide to switch the phase-change cell between its crystalline and amorphous states. Such switching results in a non-volatile and reversible alteration of the waveguide’s optical transmission, thus forming the basis of the readout process. In terms of detecting the readout signal, a high signal-to-noise ratio (SNR) is obviously desirable. Optimising readout SNR involves a trade-off between readout contrast and insertion loss. Here we explore role of cell size and the size of the written mark on the readout signal, developing a realistic figure-of-merit to help guide design choices and deliver an optimum readout signal.