A Fiber-Optic Microbending Temperature Sensor

A fiber-optic amplitude sensor based on the effect of microbending-caused upsetting of total internal reflection and intended for temperature monitoring is described. A measuring-system prototype was developed for investigating the sensor characteristics. The measured sensor characteristics show that a sensor with alcohol as the working fluid has a maximum sensitivity of 1.9 × 10−2°C−1. The range of linear variation of its normalized optical output signal was 0.829. The temperature range was 42.5°C, the maximum temperature being 74.5°C. It is shown that several sensors of this type can be integrated in fiber-optic lines to be used in distributed fiber-optic measuring networks.