All-Photonic Micro-Sensor Based on Whispering Gallery Mode Resonators

B. Snider, T. Ippolo, V, Otugen, B. Gnade
Southern Methodist University, Texas, United States

Keywords: Sensor, photonics, accelerometer, vibration, acoustic waves

An optical micro-sensor based on Whispering Gallery Mode (WGM) shifts in a dielectric cavity offers the possibility for both low cost and high performance for acoustic/seismic sensing. The WGMs are optical modes of dielectric cavities excited by coupling Laser light through an optical fiber. The optical resonances of the cavity are observed as sharp dips in the transmission spectrum at the fiber output. A change in the shape of the cavity is detected by monitoring the optical wavelength shift. With the size of the cavity at approximately 100 microns, in principle, a change of 10-11 meters could be detected. Historically, building large networks of acoustic/seismic sensors has been prohibitively expensive due to the combination of costs of the sensors, building the network of sensors, and deployment and maintenance of these networks. A WGM-based integrated sensor network can revolutionize all the cost aspects listed above, and dramatically improve the performance of these sensor networks. This proposed sensor network could then be a throw away device for many DTRA, DoD, and DHS applications