Silicon photonic dual-gas sensor for H2 and CO2 detection

We report a silicon photonic dual-gas sensor based on a wavelength-multiplexed microring resonator array for simultaneous detection of H-2 and CO2 gases. The sensor uses Pd as the sensing layer for H-2 gas and a novel functional material based on the Polyhexamethylene Biguanide ( PHMB) polymer for CO2 gas sensing. Gas sensing experiments showed that the PHMB-functionalized microring exhibited high sensitivity to CO2 gas and excellent selectivity against H-2. However, the Pd-functionalized microring was found to exhibit sensitivity to both H-2 and CO2 gases, rendering it ineffective for detecting H-2 in a gas mixture containing CO2. We show that the dual-gas sensing scheme can allow for accurate measurement of H-2 concentration in the presence of CO2 by accounting for the cross-sensitivity of Pd to the latter. (C) 2017 Optical Society of America