  This paper presents formulae for Einstein-Podolsky-Rosen (EPR) entanglement
generated from $N$ nondegenerate optical parametric amplifiers (NOPAs)
interconnected in a linear coherent feedback (CFB) chain in the idealized
lossless scenario and infinite bandwidth limit. The lossless scenario sets the
ultimate EPR entanglement (two-mode squeezing) that can be achieved by this
linear chain of NOPAs while the infinite bandwidth limit simplifies the
analysis but gives an accurate approximation to the EPR entanglement at low
frequencies of interest. Two adjustable phase shifts are placed at the outputs
of the system to achieve the best EPR entanglement by selecting appropriate
quadratures of the output fields.
