Various types of fiber-optic sensors are used in composite materials for structural health monitoring. Whispering gallery mode (WGM) sensors are a special class of micro-optical sensors that are created by optical coupling of a dielectric microparticle and an optical fiber. Such sensors have potential to be used in particulate and fibrous composites to measure stress or strain. The combination of particle and optical-fiber to create sensor requires encapsulating them in a suitable material to incorporate in the composite material. The sensitivity of the encapsulated sensor needs to be calibrated before they can be used in actual applications. The present study uses modeling and simulation approaches to develop theoretical estimates of sensitivity of the encapsulated WGM sensors. Solid and hollow microparticles are considered for the study. Hollow microparticles provide higher sensitivity than solid particles of the same material because of their lower effective elastic modulus, providing higher strain for the same applied force.