CO/sub 2//H/sub 2/O gas sensor using a tunable Fabry-Perot filter with wide wavelength range

An electrostatically driven tunable MEMS Fabry-Perot filter (FPF) with wide wavelength range from 2.5 /spl mu/m to 4.5 /spl mu/m has been developed for non-dispersive infrared (NDIR) CO/sub 2//H/sub 2/O gas sensors. The electrostatic discharge (ESD) test and the long-term repetition-stability test were carried out for the FPF and no remarkable change of FPF performance was observed in either test. An NDIR system was equipped with the FPF, and the principle of the gas sensing method was confirmed. The resolutions defined by standard deviation are about 13 ppm for CO/sub 2/ of 2000 ppm and 0.35 g/m/sup 3/ for H/sub 2/O Of 22.5 g/m/sup 3/.