Bending-resistant optical fiber for ultra-sensitive distributed sound wave sensing

The invention belongs to the technical field of optical fiber sensing, and particularly provides an anti-bending optical fiber for ultra-sensitive distributed sound wave sensing, which is used for ensuring the anti-bending performance and transmission loss of the optical fiber after grating inscribing. The optical fiber comprises an outer cladding layer, a refractive index sunken layer, an inner cladding layer, an outer core layer and an inner core layer which are sequentially arranged from outside to inside in a wrapping mode. The refractive index of the outer core layer is higher than that of the inner cladding layer and lower than that of the inner core layer, the inner cladding layer is made of pure quartz, the refractive index of the refractive index sunken layer is lower than that of the inner cladding layer, and the outer cladding layer and the inner cladding layer are made of the same material; by adding the outer core layer with lower refractive index, part of light is transmitted in the outer core l