Wavelength Reuse in Passive Optical Network for Polarization Based Environmental Sensing

We propose and experimentally demonstrate a cost-effective technique of optical sensor that utilizes the reused wavelength in the customer's premises. This has been achieved by utilizing the saturated EDFA to suppress the extinction ratio of the incoming optical signal hence erasing the downstream data allowing for channel reuse. A 1550nm distributed feedback (DFB) laser is directly modulated with a 10 Gbit/s NRZ data signal and used to characterize the erasing functionality of EDFA. The performance evaluation is done for different input power into the EDFA. The EDFA is shown to reduce the extinction ratio of the incoming signal from 6.48 dB to 0.81dB when the input powers of −7.3 dBm and 1.1 dBm were respectively used, therefore facilitating the direct reuse of the downstream carrier. The vibrational sensor was demonstrated at 85 MHz and the signal was fully recovered. These results indicated the ability of the sensor to detect a change in the environment, therefore giving an early warning signal. The optical fiber sensor system proved to be a reliable and cheaper alternative for environmental monitoring utilizing re-used wavelength.