Microring-resonator-based sensor measuring both the concentration and temperature of a solution

We propose and investigate experimentally a micro-ring-resonator-based sensor with which we can measure both the concentration and temperature of glucose solution. It consists of two micro-ring resonators consecutively coupled to a bus waveguide by the overlap between them. The resonance wavelengths of the two resonators change similarly with the temperature but differently with the concentration. For that purpose, the core of just one micro-ring resonator is exposed directly to the solution. Using polymers, conventional processes, and a polymer lift-off process, we implement the sensor. Through the measurement of the fabricated sensor, we obtain its characteristics of measuring the temperature and concentration. (C) 2008 Optical Society of America.