“…Optical fiber sensors [1][2][3][4][5][6][7][8][9][10][11][12][13] have attracted considerable attention in the past several decades due to their wide applications for a great variety of measurements such as temperature, strain, chemical concentration, refractive index, hydrostatic pressure and their advantages such as small size, light weight, high sensitivity, multiplexing capability, and immunity to electromagnetic interference. Among them, several hydrostatic pressure sensing techniques have been developed, which include hydrostatic pressure sensors based on birefringent fibers [14][15][16], photonic crystal fibers (PCFs) (or microstructured fibers) [17][18][19][20][21][22][23][24], fiber Bragg gratings (FBGs) [18], and Fabry-Pérot interferometers (FPIs) [25][26][27].…”