▎ 摘　　要

Application of the Fabry-Perot (FP) interference method for determining the coefficient of thermal expansion (CTE) of a graphene diaphragm is investigated in this paper. A miniature extrinsic FP interferometric (EFPI) sensor was fabricated by using an approximate 8-layer graphene diaphragm. The extremely thin diaphragm was transferred onto the endface of a ferrule with an inner diameter of 125 mu m, and van der Waals interactions between the graphene diaphragm and its substrate created a low finesse FP interferometer with a cavity length of 36.13 mu m. Double reference FP cavities using two cleaved optical fibers as reflectors were also constructed to differentially cancel the thermal expansion effects of the trapped gas and adhesive material. A temperature test demonstrated an approximate cavity length change of 166.1 nm degrees C-1 caused by film thermal expansion in the range of 20-60 degrees C. Then along with the established thermal deformation model of the suspended circular diaphragm, the calculated CTE ranging from -9.98 x 10(-6) K-1 to -2.09 x 10(-6) K-1 conformed well to the previously measured results. The proposed method would be applicable in other types of elastic materials as the sensitive diaphragm of an EFPI sensor over a wide temperature range.