Towards a Robust Multiply-Accumulate Cell in Photonics using Phase-Change Materials
Raphael Cardoso, Clément Zrounba, Mohab Abdalla, Paul Jimenez, Maurício Gomes de Queiroz, Benoı̂t Charbonnier, Fabio Pavanello, Ian O’Connor, Sébastien Le Beux · 2023
In this paper we propose a novel approach to multiply-accumulate (MAC) operations in photonics. This approach is based on stochastic computing and on the dynamic behavior of phase-change materials (PCMs), leading to the unique characteristic of automatically storing the result in non-volatile memory. We demonstrate that, even with perfect look-up tables, the standard approach to PCM scalar multiplication is highly susceptible to perturbations as small as 0.1% of the input power, causing repetitive peaks of 600% relative error. In the same operating conditions, the proposed method achieves an average of 7× improvement in precision.