Strain-Induced Spectral Tuning of the Whispering Gallery Modes in a Cylindrical Micro-Resonator Formed by a Polymer Optical Fiber
Document Type Article
Applied Optics, Vol. 56, No. 5 / February 10 2017
Abstract
A mechanical strain assisted technique for spectral tuning of whispering gallery modes (WGM) in a cylindrical micro-resonator formed by a polymer optical fiber (POF) is investigated. WGMs in the POF based micro-cylinder are excited by evanescent light coupling using a tapered single mode silica fiber. WGMs observed in the transmission spectrum of the silica fiber taper have a high extinction ratio of up to 19 dB and a Q-factor of up to 2.64 × 104. The application of tensile axial strain (μɛ) in the range from 0 to 1746 μɛ (0.17 %) to the POF micro-resonator results in a linear shift of the WGM spectrum with a sensitivity of 0.66 pm/μɛ. Under the influence of the applied strain the WGMs undergo a blue shift and return to their initial spectral positions after the strain is decreased. The proposed strain-tunable POF micro-resonator has potential applications in fiber optic sensing and tunable micro lasers.