Integration of FBG Optical Sensor Network in DWDM-PON Transmission System

Currently, the world is experiencing fast development and creation of new fiber optical technologies and solutions, which require to analyze them in combination with each other. One of such technologies, which is widely used and researched is fiber Bragg grating (FBG) sensing technology. It has significant advantages compared to mechanical and electrical sensors, like high sensitivity, immunity to electromagnetic interference (EMI), easy to multiplex several FBG sensors on one optical fiber, etc. These advantages provide the successful usage of fiber optical sensors for roads, bridges, railways, and tunnel monitoring - so-called structural health monitoring (SHM) applications, to evaluate temperature, strain, pressure, moisture, etc. In this paper, by using simulation software, we demonstrate the realization and coexistence of fiber optical sensors network embedded in a multichannel dense wavelength division multiplexed passive optical network (DWDM-PON). For this research, the experimental simulation setup that consists of 16 and 50 GHz spaced non-return-to-zero on-off keying (NRZ-OOK) modulated DWDM-PON transmission system channels operating with bit rate of 10 Gbit/s and seven FBG optical temperature sensors network was developed. Not only the channel spacing (spectral guard band) between FBG sensors has a significant role on the performance of sensors network, but also the connecting single-mode optical fiber (SMF) length between them is an important aspect to assess, especially considering the reach of fiber optical sensor network in connection with SHM sensing necessities, as for an example - long length transportation infrastructures, like roads, near which the fiber optical cables are typically deployed. Therefore, we research the impact of the FBG sensors network on the DWDM-PON transmission system and their coexistence in one system, as well as the maximum SMF fiber length from the FBG sensors interrogation unit to the last sensor, is determined and evaluated.