Interchannel nonlinear transmission penalties in polarization-multiplexed 2x10 Gbit/s DPSK

We discuss the performance of a multichannel 2 3 10 Gbit/s polarization-multiplexed differential phaseshift keying transmission system. Through simulations and transmission experiments we find that, despite the constant power envelope of non-return-to-zero phase-shift keying modulation formats, polarization multiplexing strongly reduces the nonlinear tolerance and transmission performance at a 2 3 10 Gbit/s line rate with multichannel transmission. This results in a 10 dB power penalty when comparing single- and nine-channel transmission. Additionally, multichannel impairments in differential phase-shift keying and on–off keying are compared for 2 3 10 Gbit/s polarization-multiplexed transmission. © 2005 Optical Society of Americ