Embodiments of the present disclosure are directed towards a micro-electromechanical system (MEMS) sensing device, including a laser arrangement configured to generate a light beam, a first waveguide configured to receive and output a first portion of the light beam, and a second waveguide having a section that is evanescently coupled to the first waveguide and configured to receive and output a second portion of the light beam. The section of the second waveguide is configured to be movable substantially parallel to the first waveguide, wherein a movement of the section of the second waveguide may be caused by an inertial change applied to the sensing device. The movement of the section may cause a detectable change in light intensity between the first and second portions of the light beam. Based on the detected change, the inertial change may be determined. Other embodiments may be described and/or claimed.