Hetero-core spliced optical fiber SPR sensor system for soil gravity water monitoring in agricultural environments

•A real-time soil gravity water monitoring system with hetero-core splice SPR sensor.•Data communications and sensing are handled in the same line simultaneously.•Longer data transmission is achieved using a tantalum pentoxide coating.•The system has succeeded to realize sensing and data communications simultaneously.

This paper presents a hetero-core spliced optical fiber surface plasmon resonance sensor system for soil gravity water monitoring in agricultural environments. The present system simultaneously provides data communications and sensing functions over the same optical fiber line. The sensor is covered with tantalum pentoxide, which allows data transmission distance to be extended with a wavelength of 1310 nm for wide-area monitoring. This sensor system can gather remotely observed environmental data from monitoring points and deliver them to users on a real-time basis.