Asymmetrical bidirectional optical wireless communication system based on a transmissive 1D LC SLM for NG PON2.
An asymmetric bidirectional optical wireless communication (B OWC) system using optical fibers as the transmitter and receiver and capable of wavelength switching is proposed for next generation passive optical network stage two (NG PON2) extension to home area network (HAN) without optical/electrical (O/E) and electrical/optical (E/O) conversions, which is based on a transmissive "floating" pixel size one dimensional (1D) liquid crystal spatial light modulator (LC SLM) at the access node (AN) and a modulated retroreflector (MRR) at the terminal user (TU) The utilization of a reflective grating element and a low cost LC SLM in the AN offers a high flexibility of beam steering and wavelength selection in the scenario of B OWC. Instead of a light source used at conventional TU, a MRR was employed at a TU in order to improve the problems of the power consumptions, alignment difficulties, wavelength contentions, and cost of the TUs. Downlink and uplink data transmissions at a link speed over 2.5 Gbits/s, using wavelengths between 1590~1603nm and 1524~1544nm, respectively, corresponding to the downlink and uplink wavelengths specified by the NG PON2 standard, have been experimentally demonstrated successfully, with quality factors (Q factors) beyond the forward error correction limit (Q factor=16.9dB, bit error rate=10 12)
Optics letters