Highly accurate temperature sensor using two fiber Bragg gratings

A new highly accurate temperature sensor for biomedical applications is proposed. The sensor, including two fiber Bragg gratings with different thermal coefficients, can accurately measure temperature with little laser frequency stabilization. A general theoretical model is established and the performance is analyzed. Some numerical examples from 0.1 /spl deg/C to 10 /spl deg/C temperature shift around human body temperature are presented. The novel method immunizes temperature sensing against the frequency drifting of the light source.