Experimental Demonstration of an LCoS-Based Access Node for Bidirectional Optical Wireless Communications

Abstract

An liquid crystal on silicon (LCoS)-based access node using optical fibers as the transmitter and receiver to deliver high-speed data transmission is proposed and experimentally demonstrated. This access node can be applied to a variety of networks ranging from passive optical networks to indoor home area networks through optical wireless communications without optical/electrical/optical (O/E/O) conversions. The link of system, which operates over ∼2.5 m with a possible wide field-of-view of nearly 97°, has been achieved through the implementation of a LCoS-based spatial light modulator in conjunction with a static grating element. A bidirectional optical wireless communication system was established to demonstrate the concept and evaluate the performance of the proposed access node, which uses typical WDM wavelengths (the channel spacing is 100 GHz) and is modulated at a data speed of more than 2.5 Gb/s. The results show that in downlink transmission, the multiple wavelengths delivered from optical fibers can be dynamically transmitted directly to the terminal users through the proposed access node architecture without performing any O/E/O conversion. Similarly in uplink transmission, all the wavelengths received at the proposed node architecture can be arbitrarily switched to a desired output fiber port of the access node to connect with the external fiber networks in the same manner. The bit error ratios of all the transmitted wavelengths in both uplink and downlink transmission scenarios are less than 10-9.