An optically-powered integrated microstructure pressure sensing system for sensing pressure within a cavity. The pressure sensing system comprises a pressure sensor having an optical resonant structure subject to the pressure within the cavity and having physical properties changing due to changing pressures within the cavity. A substrate supports the optical resonant structure. An input optical pathway evanescently couples light into the optical resonant structure. An output optical pathway collects light from the optical resonance structure. A light source delivers a known light input into the input optical pathway whereby the known light input is evanescently coupled into the optical resonant structure by the input optical pathway and a portion of such light is collected from the optical resonant structure by the output optical pathway. A light detector receives the portion of the light collected from the optical resonant structure, and generates a light signal indicative of such portion of the light collected from the optical resonant structure. A temperature compensation sensor generates a temperature signal indicative of the temperature near the optical resonant structure. A spectrum detection device receives the light signal and temperature signal. The spectrum detection device analyzing the light signal and the temperature signal with a detection algorithm to generating a pressure signal indicative of the pressure within the cavity.