# Temperature-Compensated Vector Bending Sensor with Double-Cladding Fiber Assisted Mach–Zehnder Interferometer

## TL;DR

A new temperature-compensated bending sensor using fiber optics is developed for precise curvature measurements in small spaces.

## Contribution

A compact, temperature-compensated vector bending sensor using a double-cladding fiber-assisted Mach–Zehnder interferometer is proposed.

## Key findings

- The sensor achieves a high curvature sensitivity of −8.311 nm/m−1.
- It maintains direction sensing and temperature compensation capabilities in a 3 mm compact size.

## Abstract

Vector bending sensing is an important research direction in the field of bionic robot design. A vector bending sensor with temperature compensation based on Mach–Zehnder interferometer (MZI) is proposed and experimentally investigated. The MZI is implemented using an off-axis splice between a single-mode fiber (SMF) and a double-cladding fiber (DCF). The proposed sensor is analyzed comprehensively from the perspective of theoretical analysis and experimentally demonstrated. It reaches a high curvature sensitivity as high as −8.311 nm/m−1 and a compact size as small as 3 mm, while keeping the capability of direction sensing and temperature compensation. The proposed vector bending sensor has a good potential for accurate curvature measurement due to its high accuracy, multifunction, low cost and, compact size.