Chirped fiber Bragg grating coupled with a light emitting diode as FBG interrogator

Due to rising demand for smart infrastructure systems, cost-effective, efficient and reliable sensing systems are needed more than ever. In this paper, a novel fiber Bragg grating (FBG) interrogation system is proposed in which very few optical components are employed. In the proposed system, light from an LED is coupled into a chirped (CFBG). The light transmitted through the CFBG is received by a photodiode to measure its power, which is interrogated to measure the change in strain or temperature in the CFBG. A highly stable current driver supplies current to the LED to generate a stable LED output. The presented system is of low power, simple, compact, robust and cost-effective with a strain measurement resolution of about 6 με. The user convenience can be greatly enhanced by integrating the system with a wireless electronic module.