A pulsed source of continuous variable polarization entanglement

We have experimentally demonstrated polarization entanglement using continuous variables in an ultra-short pulsed laser system at the telecommunications wavelength of 1.5 mum. Exploiting the Kerr non-linearity of a glass fibre we generated polarization squeezed pulses with (S) over cap (2) as the only non-zero Stokes parameter, thus (S) over cap (1) and (S) over cap (3) being the conjugate pair. Polarization entanglement was generated by interference of the polarization squeezed field with a vacuum on a 50:50 beamsplitter. The two resultant beams exhibit strong quantum noise correlations in (S) over cap (1) and (S) over cap (3). The sum noise signal of (S) over cap (3) was at the respective shot noise level and the difference noise signal of (S) over cap (1) fell -2.9 dB below this value.