75GBAUD NYQUIST QPSK SIGNAL TRANSMISSION WITH ORBITAL ANGULAR MOMENTUM MULTIPLEXING

摘要

In this article, for the first time the generation, multiplexing, and detection of 75GBaud Nyquist QPSK signal transmission over two orthogonal Laguerre-Gaussian modes carrying orbital angular momentum (OAM) were experimentally demonstrated. To further increase spectrum efficiency, Nyquist signal was generated by all-optical method to produce sinc-shaped Nyquist pulses and received by full-band signal coherent detection with digital signal processing. Two OAM modes with same absolute value of charge but opposite sign were generated, multiplexed, and demultiplexed. The bit error ratio performance of the received signal was under forward error correction threshold with optical signal-to-noise ratio of 20 and 22 dB for +8 mode and -8 mode, respectively. To our best knowledge, this is the highest baud rate ever achieved in OAM based wireless optical transmission systems, which clearly validate the feasibility and benefit of Nyquist signal transmission with OAM mode multiplexing to increase the spectrum efficiency and system capacity. (C) 2016 Wiley Periodicals, Inc.