Sensor data transmission overlay on gigabit passive optical networks

We propose and experimentally demonstrate overlaying an independent channel on a gigabit passive optical network (GPON). This has application to carry data collected from wireless sensor networks used for environmental monitoring on a public network. The overlaid channel, which utilizes highly stretched pulses to carry the low-rate sensor data, is unnoticeable in the presence of ordinary data channels. This overlaid channel can provide security for the sensor data because of its ultralow signal amplitude. Our experiment demonstrates that the GPON transmission experiences minimal performance degradation from the overlaid channel, indicating the feasibility of our approach. A cost-effective system architecture is proposed, and theoretical analysis shows the effect of the sensor data signal on the GPON data transmission performance.