Development of fabrication technique and sensing performance of optical fiber humidity sensors in the most recent decade

The control and measurement of humidity are closely related to the daily-life of human. The accurate measurement of humidity plays an important role in food safety, environmental monitoring, agricultural production, industrial manufacturing and other aspects. The main research achievements for the optical fiber humidity sensors in the past ten years are reviewed and discussed. Several key principles are classified and introduced, as well as the sensing performance of different types of sensors are compared and discussed. By analyzing the main problems of existing optical fiber humidity sensors, the future development is prospected.