Temperature compensation techniques for resonantly enhanced sensors and devices based on optical microcoil resonators

It is well known that environmental effects have a major influence on the optical stability of resonantly enhanced sensors and devices based on optical microfiber, namely in the configuration of a microcoil resonator. We propose a geometric design to reduce such effects by chirping the refractive index of successive paired turns in the microcoil resonator. The resistance to external effects such as temperature drifts can be considerably improved by optimizing the coupling coefficients and chirping profile, such that the wavelength span of the resonant condition is maximized without compensating its sensitivity to the desired measurand. We also demonstrate another technique based on resonant wavelength tuning using a compact piezoelectric ceramic disk measuring 3 mm in diameter and 1 mm in thickness, attaining tunability as high as 6.5 pm/100 V. (C) 2012 Elsevier B.V. All rights reserved.