Miniaturized Whispering Gallery Mode (WGM) temperature sensor has great potentials of high resolution and great on-chip integration capability. This study focuses on the development of this kind of sensor based on the shifting wavelength of the optical resonance due to thermal expansion and thermo-optic effects of a silica microsphere. Excellent linear dependence of the wavelength shift versus temperature rise is observed for three sizes of microspheres (D=90μm, 145μm and 313μm) in small temperature ranges (≤17K) at very low temperatures (113±1K to 173K). By comparing this observation with the results of similar sizes of microspheres of our previous study in near room temperature as well as with a theoretical analysis, a conclusion is drawn that thermal expansion and thermal optic coefficients need to be further studied for microscale silica materials. Ultra high resolution sensing capability as well as potentials of integrated & miniaturized applications of the WGM temperature sensor is discussed. A method is designed to initially characterize the WGM temperature measurement noise level due to self-heating effect of the WGM resonance.

Date Published: 24 August 2009
PDF: 12 pages
Proc. SPIE 7420, Photonic Fiber and Crystal Devices: Advances in Materials and Innovations in Device Applications III, 74200Q (24 August 2009); doi: 10.1117/12.827417

Published in SPIE Proceedings Vol. 7420:
Photonic Fiber and Crystal Devices: Advances in Materials and Innovations in Device Applications III
Shizhuo Yin; Ruyan Guo, Editor(s)