Optical Filter-Based FBG Sensor Interrogator Unit for Low-Cost Sensing

Fiber Bragg grating (FBG) optical sensors have excellent sensitivity, small size, and immunity to electromagnetic interference. These characteristics make them appealing for a wide range of applications. However, a rather expensive data processing equipment limits practical applicability especially in cases of a single or couple of sensors in remote nodes. The authors propose a simple and compact FBG sensor interrogator device containing broadband light source, optical filter, small form-factor pluggable (SFP) optical transceiver-based photodetector, and microcontroller. This article describes the developed interrogator unit’s prototype and its principle of operation. It is tested using a mechanical strain FBG sensor. The estimated range of strain measurement is up to $420~\mu $ m/m and the minimum sensitivity around $2~\mu $ m/m with measurement update rate every 40 ms.