Highly Power-Efficient Nyquist-mPPM-LQAM Modulation With Enhanced Spectrum Efficiency

Nyquist-mPPM-LQAM is proposed, theoretically analyzed, and experimentally demonstrated for power- and spectrum-efficient optical modulation. Based on Nyquist shaping, Nyquist-mPPM-LQAM halves the occupied bandwidth with doubled spectrum efficiency compared with mPPM-LQAM. Taking Nyquist-4PPM-QPSK as an example, a receiver sensitivity of -49.8 dBm at BER of 1e-3, corresponding to a calculated power efficiency of 9.1 dB with a spectrum efficiency of 1 bit/s/Hz/pol, is experimentally demonstrated at 10 Gbit/s. An improvement of 1.6 dB in power efficiency is observed over QPSK at the same spectrum efficiency. Thus, the proposed format can provide high power efficiency with double spectrum efficiency compared with non-Nyquist-shaped formats.