Advanced Manufacturing, Electronics and Microsystems: TechConnect Briefs 2015Advanced Manufacturing, Electronics and Microsystems TechConnect Briefs 2015

Photonic Materials & Devices Chapter 5

Fabrication and Characterization of On-Chip Integrated Silicon Photonic Bragg Grating and Photonic Crystal Cavity Thermometers

N.N. Klimov, T. Purdy, Z. Ahmed
National Institute of Standards and Technology / University of Maryland, United States

pp. 154 - 156

Keywords: photonic thermometer

Though today’s resistance thermometers can routinely measure temperatures with uncertainties of 10 mK, they are sensitive to environmental variables such mechanical shock and humidity, which cause the sensor resistance to drift over time requiring expensive, time consuming calibrations. These fundamental limitations of resistance thermometry, as well as the desire to reduce sensor ownership cost has produced considerable interest in the development of photonic temperature sensors as an alternative to resistance thermometers. In this study we present our results on fabrication and characterization of our 1st generation silicon photonic thermometers: a waveguide Bragg grating cavity (Si WBG-C) and photonic crystal cavity (PhC-C) sensors. Both types of photonic thermometers over the range from 15 degC to 40 degC show a systematic upshift of ≈ 70 pm/degC as temperature increases. While two sensors have comparable temperature response, PhC-C has approximately 10x narrow resonance peak compared to WBG-C. We expect that the narrower linewidth of PhC-C thermometer will reduce combined measurement uncertainties by at least a factor of ten. In addition, WBG-C and PhC-C sensors allow for unambiguous determination of the fundamental mode. In summary, we have demonstrated that PhC-C and WBG-C sensors fabricated using CMOS technology are viable photonic temperature sensing solutions.