<p>In this article, we describe our new approach to experimentally determine the dynamic Young’s modulus of bare optical fiber by interrogating the natural frequency of vibration of the fiber cantilever utilizing Euler-Bernoulli cantilever beam theory coupled with fiber guiding optics. The fiber cantilever beam is set to vibrate freely by giving a sudden constant force, and its dynamic response is recorded from the locus of the far-field mode of guided light exiting the fiber tip. From the procured data set, the system’s natural frequency is then excreted by FFT analysis using MATLAB platform. Three different types of optical fibers were tested and the results agree very well with the established values reported in the literature. Furthermore, we used a finite element method (FEM) based model in the COMSOL Multiphysics platform to verify the experimental results. Next, using this cantilever device platform, we configured a viscosity measurement setup for moderately viscous liquid by immersing the system in liquid. The ‘effective spring-mass damper’ model, including added mass due to liquid loading, is used to evaluate the damping coefficient of the system. Experimentally recorded overdamped oscillation data of the cantilever beam is studied to procure the damping ratio of different liquids and determine the viscosity of fluids. We find that the results again exhibit excellent agreement for up-to 35% (v/v) glycerol-water solution. We also test the setup with ethanol and sugar solution for up-to 25% (w/w). Thus, using this fiber cantilever as a common host, we successfully demonstrate the measurement of two basic physical quantities.</p>