A Low-cost Portable Interrogator for Dynamic Monitoring of Wavelength-Based Sensors

This paper proposes a low-cost portable interrogator for dynamic monitoring of wavelength-based fiber-optic sensors such as fiber Bragg gratings (FBGs) and Fabry-Perrot interferometers (FPIs). The interrogator is based on a compact solution involving a broadband light source and the spectral convolution between the sensor and a tunable filter. The filtered signal is then acquired by a photodetector where the optical-electrical conversion happens. Additionally, a microcontroller performs three actions: (i) controls the filter tuning, (ii) acquires the photodetector signal, and (iii) sends the data to a single-board computer (SBC). Lastly, the SBC performs further signal processing and displays the sensor data on a graphical user interface. The choice for hardware and software development combined allows for a lost-cost solution that supports monitoring of four channels simultaneously, real-time operation, compatibility with Windows and Linux-based operating systems, dynamic inputs for signal processing, wireless communication with low latency, and portability.