“…Diaphragm-based fiber optic acoustic sensors have attracted much interest because of their high sensitivity [8]- [10], wide frequency band [11]- [13], and high dynamic range [14]. Several diaphragms have been used to detect acoustics waves, such as metal (silver [8], [15], gold [16], [17]), two dimension materials (graphene oxide [11]), graphene [12], [13], silicon nitride [18], [19], and polymer (PPESK [20], PET [21]- [23]). Other than metal diaphragm, the rest diaphragms face the problem of low reflectivity.…”