Interferometric humidity sensors based on microfiber knot resonators

Abstract

In this paper, three fiber-optic interferometric humidity sensors based on silica/polymer microfiber knot resonators (SMKR/PMKR) are reported. These tiny humidity sensors are directly fabricated by using silica/polymer microfibers without any humidity-sensitive coating. The silica MKR has a humidity sensitivity of ~12pm/10% RH over a range from 14% RH to 60% RH, while the PMMA (poly-methyl methacrylate) MKR has a humidity sensitivity of ~88pm/10% RH, over a range from 17% RH to 95% RH, and the PAM (Polyacrylamide) MKR with the highest sensitivity of ~270pm/% RH over the range of 10% to 62%.