Rafique, D,Mussolin, M,Martensson, J,Forzati, M,Fischer, JK,Molle, L,Nolle, M,Schubert, C,Ellis, AD

2011

January

Optics Express

Polarization multiplexed 16QAM transmission employing modified digital back-propagation

Validated

()

NONLINEARITY COMPENSATION COHERENT SYSTEMS

19

805

810

We experimentally demonstrate performance enhancements enabled by weighted digital back propagation method for 28 Gbaud PM-16QAM transmission systems, over a 250 km ultra-large area fibre, using only one back-propagation step for the entire link, enabling up to 3 dB improvement in power tolerance with respect to linear compensation only. We observe that this is roughly the same improvement that can be obtained with the conventional, computationally heavy, non-weighted digital back propagation compensation with one step per span. As a further benchmark, we analyze performance improvement as a function of number of steps, and show that the performance improvement saturates at approximately 20 steps per span, at which a 5 dB improvement in power tolerance is obtained with respect to linear compensation only. Furthermore, we show that coarse-step self-phase modulation compensation is inefficient in wavelength division multiplexed transmission. (C) 2011 Optical Society of America