An All-Fibre Optic Multifunctional Sensor Based on Large-Core Quartz-Polymer Microlens-Ended Fiber Pairs

A simple and miniature multifunctional all-fibre sensor is proposed and described. The fibre-optic sensor is based on fused large-core quartz-polymer fiber pairs and the formation of a joint microlens. The microlens-ended fibre pairs can be used to sense critical liquid level, monitor evaporation and the presence of vapors. The performance and sensitivity of the sensor is shown to depend on the degree of microbulb growth. A larger microlens favours a better liquid level and moisture sensitivity while a smaller bulb ratio is better suited for a better vapour sensing