Abstract
Passive optical network (PON) has become more and more popular with the promoting of Fiber to the Home (FTTH) and 4G Long Term Evolution (LTE) network. It is an important issue to reduce the cost of clients for commercial considerations. In this paper, we demonstrated Nyquist-QPSK for multi-band WDM-PON with coherent detection upstream system. We used both optical filtering and MATLAB coding to generate Nyquist-QPSK. Compared with conventional QPSK, Nyquist-QPSK has higher power sensitivity and smaller bandwidth, which make it highly tolerant to chromatic dispersion. On the other hand, rectangular-shape spectrum of Nyquist-QPSK leads to no need of guard bands in multi-band system and low complexity for equalizer designing. The features mentioned above make Nyquist-QPSK suitable for WDM-PON upstream to reduce the cost and improve the spectral efficiency of the systems.