  In this work, we investigate three different compact fibered systems
generating vacuum squeezing that involve optical cavities limited by the end
surface of a fiber and by a curved mirror and containing a thin parametric
crystal. These systems have the advantage to couple squeezed states directly to
a fiber, allowing the user to benefit from the flexibility of fibers in the use
of squeezing. Three types of fibers are investigated: standard single-mode
fibers, photonic-crystal large mode area single-mode fibers and short
multi-mode fiber taped to a single-mode fiber. The observed squeezing is modest
(-0.56 dB, -0.9 dB, -1 dB), but these experiments open the way to miniaturized
squeezing devices that could be a very interesting advantage in scaling up
quantum systems for quantum processing, opening new perspectives in the domain
of integrated quantum optics.
