Fiber-optic resonators for strain-acoustic sensing and chemical spectroscopy

Over the past several years, fiber-optic resonators have been used as mechanical probes by virtue of their intrinsic sensitivity to length changes, and chemical sensors based on sensitivity to molecular absorption or refractive index changes. The capabilities of high-finesse fiber Bragg-grating cavities for quasi-static and dynamic strain sensing are discussed. Pound-Drever-Hall (PDH) frequency locking techniques are considered for low-noise, fast and wide dynamic range active interrogation. Such methods can ultimately be used in combination with highly-stabilized laser sources or optical frequency combs (OFCs) which would provide both an exotic coherent radiation source and an ultra-stable optical reference at the same time. The implementation of similar systems for applications to seismic monitoring and acoustic pickup for musical instruments are described. Also, we describe detection schemes for chemical sensing and evanescent-wave spectroscopy using fiber-ring resonators, for which we propose lasers as well as supercontinuum comb generators as light sources. © 2014 Springer-Verlag Berlin Heidelberg.