Requirements on bit resolution in optical Ising machine implementations

TL;DR

This paper investigates how the low bit-resolution of optical modulators affects the performance of optical Ising machines, finding that 8-bit resolution suffices and 1-bit can even enhance performance.

Contribution

It provides the first systematic analysis of bit-resolution requirements in optical Ising machines using numerical simulations.

Findings

8-bit resolution is sufficient for various benchmark problems

1-bit resolution significantly improves performance across benchmarks

Low-resolution modulators are viable for optical Ising machine implementation

Abstract

Optical Ising machines have emerged as a promising dynamical hardware solver for computational hard optimization problems. These Ising machines typically require an optical modulator to represent the analog spin variables of these problems. However, modern day optical modulators have a relatively low modulation resolution. We therefore investigate how the low bit-resolution of optical hardware influences the performance of this type of novel computing platform. Based on numerical simulations, we determine the minimum required bit-resolution of an optical Ising machine for different benchmark problems of different sizes. Our study shows that a limited bit-resolution of 8bit is sufficient for the optical modulator. Surprisingly, we also observe that the use of a 1bit-resolution modulator significantly improves the performance of the Ising machine across all considered benchmark problems.