  Perfect inline squeezers are both spectrally pure and have identical input
and output temporal modes, allowing one to squeeze an arbitrary input quantum
state in the sole input mode on which the device acts, while the quantum states
of any other modes are unaffected. We study theoretically how to obtain a
perfect pulsed inline squeezer in twin-beam systems by considering three
commonly used configurations: unpoled single pass, poled single pass, and poled
double pass. By obtaining analytical relations between the input and output
temporal modes from the Bloch-Messiah decomposition of the discretized
Heisenberg-picture propagator, we find that a double pass structure produces a
perfect pulsed inline squeezer when operated in a frequency degenerate,
symmetric group-velocity matched type-II configuration.
