Identical broadband chirped grating interrogation technique for temperature and strain sensing

The authors propose a simple, low-cost technique for the interrogation of fibre Bragg grating (FBG) sensors. The induced mismatch between two identical broadband fibre chirped gratings is used to provide a mechanism for measuring changes in strain/temperature associated with one grating. A linear relationship with detected optical power is seen with a 10 nm chirp rate facilitating sensing ranges up to 9000 με and 750°C for strain and temperature change, respectively