Simultaneous Upstream and Inter Optical Network Unit Communication for Next Generation PON

In traditional passive optical network (PON) neighboring, optical network units (ONUs) cannot communicate directly but through optical line terminals, resulting in propagation delays, security hazards and unnecessary use of upstream and downstream bandwidth. Inter optical network unit communication (IOC) can be a promising solution for these problems. IOC is mostly demonstrated with the help of dedicated or tunable transceivers increasing the cost of the system and making it complex. Transceiver sharing is also demonstrated in the literature but this will be a bandwidth-inefficient technique. In our paper, the simultaneous transmission of IOC signal and upstream signal is demonstrated in a time-division-multiplexed PON using single transmitter and self-phase modulation-based wavelength convertor at each ONU that converts the upstream wavelength of 1310 nm to 1310.6 nm when IOC signal is being transmitted by that ONU; at the same time another ONU can transmit the upstream data at 1310 nm which results in efficient bandwidth utilization with less delays compared to the traditional PON. In our proposed design the IOC signal is reflected back by a Uniform Fiber Bragg Grating and the upstream signal is transmitted through it. This design supports a data rate of 25 Giga bits/sec.