“…Curvature sensors have been developed using hybrid long-period fiber grating and tilted FBG for improving sensitivity [4][5][6], the thin-film bridge-type optical fiber sensor array for monitoring the bending direction and curvature [7,8], superstructure FBG [9], and FBG combined with longperiod optical fiber grating with temperature compensation [10][11][12][13][14][15]. Moreover, some complex optical sensing structures and multifunctional sensing devices have been developed, and these have double-clad fiber with a depressed inner cladding for sensing the bend, refractive index, and temperature [16], a multiple-mode fiber optic structure for sensing the temperature and strain-independent curvature [17], and an FBG eccentric-cored optical fiber for measuring the strain, bend, and temperature [18]. The optomechatronic system provides solutions to complex problems by integrating optical and mechatronic technologies [19].…”