Ultra-Sensitive Arc-Shaped MZI Strain Sensor Based on Wave Vector Axial Tilt Angle Modulation

Fiber Mach Zehnder interferometer (MZI) strain sensor can be used in aerospace, semiconductor, medical and other fields. In situations where the strain is small, the sensitivity of MZI needs to be further improved. However, due to the limitation of the fiber optic elastic coefficient, the effectiveness of existing sensitization methods is limited. This article proposes a high-sensitivity arc shaped MZI strain sensor based on wave vector axial tilt angle modulation (Arc shaped MZI). Which is formed by cascading arc-shaped fiber optic and multimode fiber optic to form a fiber MZI. During the strain process, the arc shaped MZI undergoes deformation, and the wave vector axial tilt angle of the cladding mode changes. However, the change in wave vector axial tilt angle of the cladding mode is no longer limited by the fiber optic elastic coefficient, and the propagation constant of the cladding mode changes significantly during the strain process, achieving a high-sensitivity MZI strain sensor. The experimental results indicate that the strain sensitivity of Arc shaped MZI is as high as 357.23 pm/μϵ, which can be used for high-precision real-time strain detection in precision instruments with small strain changes in the future.