Polarization squeezing with photonic crystal fibers

We report on the generation of polarization squeezing by employing intense, ultrashort light pulses in a single pass method in photonic crystal fibers. We investigated the squeezing behavior near the zero-dispersion wavelength and in the anomalous dispersion regime by using two distinct fibers. We observed a maximal squeezing at 810 nm of -3.3 +/- 0.3 dB with an excess noise of +16.8 +/- 0.3 dB in the anomalous regime.

Correcting for linear and interference losses between the polarization modes, this corresponds to -6 +/- 1 dB. The ratio of squeezing to excess noise indicates the creation of a much purer state; this ratio indeed lies an order of magnitude below those squeezing experiments that exploit traditional fibers [1].

We attribute this increased state of purity to increased effective nonlinearity and to the reduction of scattering on acoustic modes in the fiber.