  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.
