OPTICAL PRESSURE SENSOR-BASED ON A MACH-ZEHNDER INTERFEROMETER INTEGRATED WITH A LATERAL A-SI-H P-I-N PHOTODIODE

We have fabricated an optical pressure sensor consisting of a Mach-Zehnder (MZ) interferometer and a thin membrane anisotropically etched into the silicon substrate underneath the measuring arm of the interferometer. The oxinitride rib-waveguides are single mode both for the TE and the TM polarization. To measure the constructive and destructive interferences at the output section of the interferometer we have integrated the rib waveguide with a lateral a-Si:H p-i-n photodiode. The number of constructive interferences measured for a given membrane deflection differs depending on TE or TM polarization.