Experimental demonstration of 100 Gb/s 50Km Downstream Using PolMux MultiCAP OSSB Transmission and Heterodyne Reception based on 10G Electronics for Passive Optical Networks

Abstract

Optical access networks are already installed throughout the world, being the cornerstone for home and office high bandwidth communications. 50 Gb/s and 100 Gb/s single-wavelength PON links are being studied as they are expected to be the next step towards the future optical access networks [1] . Many works have explored different techniques to achieve 50 Gb/s links using 25 GHz or 10 GHz bandwidth components and IM/DD schemes. While 25G based solutions are usually based on PAM4, which provides a simple solution by doubling the bit count [2] , 10G based solutions need to increase even more the bit count per Hz, so most of the proposals use OFDM or Multi-CAP modulation schemes [3] – [4] . However, all these non-coherent solutions present poor sensitivities at the receiver, needing to increase the signal power at transmission to achieve adequate optical power budgets. Moreover, these schemes suffer from power fading at some frequencies when propagating through the optical fiber. In this work, we use Multi-CAP modulation as well as an optical Hilbert transformed OSSB scheme [5] for the transmission of spectrally efficient signals. This allows using power and bit loading capabilities and flexibility of the Multi-CAP modulation to transmit a 50 Gb/s bitrate while maintaining a narrow electrical and optical spectral bandwidth of 11.25 GHz, allowing the use of 10G electronics at both, transmitter and receiver side and avoiding the power fading issue without any additional digital processing. At the receiver side, we use a well-known polarization-insensitive heterodyne coherent scheme that will boost the sensitivity of the receiver and eliminate the use of tunable optical filters in a WDM system. Moreover, we use it as a PolMux receiver to double the data rate by inserting two 50 Gb/s orthogonal polarizations for an aggregated 100 Gb/s downstream link. This receiver presents a sensitivity of -22 dBm BTB and ~2dB penalty over 50 km transmission link. The obtained optical power budget is about 21 dB for the worst Multi-CAP band and PolMux channel.