50-km Remote Electronic-Sensor Integration in Fiber Optic Networks using Power over Fiber and Microelectromechanical Modulators

This work presents a power-efficient solution that combines and enables the use of electronic devices in fiber optic networks for environmental monitoring. The system is based on a frequency encoding scheme of the sensor data, which modulates the optical carrier via a microelectromechanical (MEMS) variable optical attenuator (VOA). We demonstrate a remote battery-less sensor node, powered exclusively by power-over-fiber (PoF), over a 50-km standard telecom link, using energy harvesting techniques. As a proof-of-concept, a low-power microcontroller encodes the data from electronic sensors of temperature, eCO2, and pressure in a frequency pattern, which are used as modulating signals. A Frequency Shift Keying (FSK) modulation was implemented, resulting in data rates of up to 1.5 kbps at the maximum corner frequency value of the modulator. The retrieved and decoded data were transmitted via a second optical fiber segment, extending 50 km.