Very-high-throughput coherent ultradense WDM-PON based on nyquist-ISB modulation

We propose and experimentally demonstrate a very-high-throughput coherent ultradense wavelength division multiplexing passive optical network (UDWDM-PON) with its bandwidth efficiency enhanced using Nyquist-independent-sideband (N-ISB) modulation. The proposed optical line terminal (OLT) suggests 75 downlink optical subcarriers. For each optical subcarrier, there are as many as 16, 10-Gb/s N-ISB digital channels modulated on it, which can be efficiently generated using only one set of optical transmitter hardware. Experimental results show that the proposed UDWDM-PON is capable of accommodating 1200 10G users within an optical distribution network loss budget of 35.5 dB, and achieve a total throughput of 12 Tb/s and a spectral efficiency of 5.628-b/s/Hz. More importantly, the proposed system with spectral-and bandwidth-efficient N-ISB requires 16 times less downlink optical transmitters at the OLT, which can be translated into savings in cost, power consumption, and footprint. In addition, key techniques, such as N-ISB modulation in a PON system, frequency-locked optical multicarrier generation, and digital pre-equalization, are also studied.