Detection of high spectral efficiency 16/32QAM-OFDMA downlink signals using self mixing method and its application in PON

Abstract

A passive optical network (PON) fiber access system with two types of high spectral efficiency orthogonal frequency division multiple access (OFDMA) downlink signals is designed and demonstrated. In this scheme, 50Gbit/s 16/32 quadrature amplitude modulation (QAM) -OFDMA-PON downstream signals are transmitted over 20 km single-mode fiber (SMF) and detected using self mixing detection method, in which 256 subcarriers are divided into four sub-channels for multiple users access applications. The electrical frequency spectrums, optical spectrums, constellation diagrams, and bit error rate (BER) performance of the downstream signals are analyzed. The results show that under different received optical powers, we can select a certain sub-channel with the lowest BER, and the system also supports the dynamic selection of the appropriate signals type between 16QAM-OFDM and 32QAM-OFDM according to different users bandwidth requirements.

A novel dual polarization multiplexing RoF system integrating optical fiber and FSO channel with AMI downlink signals

“…To match the RF phase information, two adjustable phase shifters and two mixers are used for self-homodyne reception. The self-mixing detection is used to eliminate the need of a local oscillator source and reduce the system cost budget [ 19 ]. Two baseband signals are filtered out by using two low pass filters (LPFs).…”