Parametric amplification of 112 Gbit/s polarization multiplexed DQPSK signals in a fiber loop configuration

Parametric amplification of 112-Gbit/s-33%-RZ-DQPSK signals with 20 dB on-off-gain is shown using highly nonlinear fiber in a polarization diversity configuration. The measured OSNR penalty at a BER of 10⁻⁴(10⁻⁹) is about 0.3 dB (1 dB).