Transmitter-Side Digital Back Propagation With Optical Injection-Locked Frequency Referenced Carriers

A 100% reach extension is demonstrated in a coherent four-channel wavelength division multiplexed system by employing full-bandwidth frequency-referenced transmitter-side digital back propagation. Frequency referenced optical carriers are generated by injection locking distributed feedback lasers to a reference optical frequency comb and the performance of digital back propagation is evaluated with and without the frequency reference. In addition, we investigate the effect of an implementation with reduced computational complexity by limiting the number of steps-per-span used in the back propagation computation. Lastly, we measure the penalties generated by an inaccurate fiber dispersion parameter in the back propagation model.