A simple and inexpensive optical power monitor for two visible wavelength WDM channels in plastic optical fibre links

Abstract

This paper shows for the first time, to the best of our knowledge, the design of a simple, non-invasive, bidirectional and inexpensive optical power monitor (OPMo) for WDM over PMMA-based polymer optical fibre (POF) links transmitting 470 nm and 650 nm wavelengths light carriers. Low-cost cellophane plastic optical filters were used for each WDM channel aiming to demonstrate the OPMo operational principle. The OPMo is non-invasive because it does not tap any guided light from the fibre core; rather, it collects and detects the spontaneous side-scattered light. A sensitivity of −32 dBm and dynamic range of 38.8 dB were measured. A crosstalk rejection better than 25 dB was achieved when both light carriers are of the same power.