Self-interference of long-period fibre grating and its application as temperature sensor

The authors describe self-interference fringes created in a single long-period fibre grating (LPG) formed in a double-cladding fibre, one end of which is coated with a metal film. The temperature-induced fringe-shift in the reflection spectrum of the proposed LPG device was measured to be 0.055 nm/°C with 0.9°C RMS deviation. Applications of such devices as filters and fine temperature sensors are expected