  In this work we examine the entanglement of the output signal-idler squeezed
vacuum state in the Heisenberg picture as a function of the coupling and
internal propagation loss parameters of a microring resonator. Using the
log-negativity as a measure of entanglement for a mixed Gaussian state, we
examine the competitive effects of the transfer matrix that encodes the
classical phenomenological loss, as well as the matrix that that incorporates
the coupling and internal propagation loss due to the quantum Langevin noise
fields required to preserve unitarity of the composite system,(signal-idler)
and environment (noise) structure.
