Polarization insensitive wavelength conversion for 4x112Gbit/s polarization multiplexing RZ-QPSK signals

In this paper, polarization-insensitive wavelength conversion based on orthogonal-pumps and four-wave mixing in HNLF is experimentally demonstrated for high-speed 112-Gb/s PolMux-RZ-QPSK transmission with digital coherent detection. The conversion performance of the proposed scheme is investigated for both single- and four-channel input signals, with the achieved post-conversion OSNR for the two cases shown to be 30 and 20 dB, respectively. Moreover, it is shown that the OSNR of the converted single-channel signal can be maintained above 25 dB even if the wavelength spacing between the original and converted signals is larger than 25 nm. Finally, the BER of 4x112-Gb/s PolMux-RZQPSK converted signals after 1 km HNLF transmission is measured to be below 1x10(-4). The optimum OSNR and launched HNLF power are also investigated.