Performance Evaluation of A Unique Distributed Polymer Optical Fiber Sensors in Humidity Monitoring

Humidity monitoring plays a great significance in a wide range of applications and industries nowadays. However, fiber optic sensors (FOS) technology which have caught the attention of researchers are yet to be widely commercialize in the market due to its complexity and one-probe-to-one-detector sensing technique. This study presents a unique distributed polymer optical fiber (DPOF) sensing system coated with plaster of Paris (PoP) to evaluate its performance in humidity monitoring. The sensing system are made up of a flexible LED lamp belt, attached to treated POF with side-coupling units. The objective is to develop an affordable, scalable, and easily deployable water sensing system for offsite monitoring application, especially in smart agriculture. By utilizing a multiplexed design, multiple sensing points can be simultaneously monitored using a single optical fiber. The experimental evaluation of the PoP-coated DPOF sensors demonstrates promising results in terms of stability, accuracy, repeatability and reliability. Statistical analysis demonstrated the independence of each sensing point, with no significant difference in intensity output when water was added to other points. The PoP coating, with its exceptional water absorption properties, enhances the sensitivity of the POF sensors to changes in humidity levels, enabling accurate monitoring in a wide range of environmental conditions. Overall, this study provides valuable insights into the capabilities, limitations, and future potential of the DPOF system coated with POP, paving the way for advancements in smart agriculture technology.