  We present a new scheme to efficiently establish entanglement between optical
modes in a time-multiplexed coherent Ising machine (CIM) by means of nonlocal
measurement and feedback. We numerically simulate and evaluate the generation
of steady-state entanglement in a system with nearest-neighbor interactions on
a 1D ring, and we compare the results to those of a conventional CIM with
all-optical interactions mediated by delay lines. We show that the delay-line
architecture has a fundamental limit on accessible entanglement that our
measurement-based scheme can substantially surpass. These results motivate the
study of non-classical correlations in CIMs with levels of entanglement
previously considered to be experimentally impractical.
