LAUSR

A strain sensing element in a high temperature environment is presented and experimentally demonstrated. The proposed strain sensing element consists of polyimide-coated fiber Bragg grating (FBG) and double rhombus metal structure. The polyimide-coated FBG was fabricated on the double rhombus metal structure by a modulated low softening glass process. The double rhombus metal structure was made of high temperature constant modulus alloy. The sensitivity of the strain sensing element is enhanced by two times of strain amplification and could be adjusted by selecting the angle and the dimension of the double rhombus metal structure appropriately. It is experimentally demonstrated that the proposed strain sensing element could be used at the high temperature of 300°C, and the average wavelength sensitivity of the strain sensing element at 300°C is 3.049 and 3.259  pm/μϵ for the compressed and stretched states, respectively.