MEMS example: Optically-interrogated pressure sensors
why use optical sensing?
- use in hostile environments
- immunity from EMI/noise
Fabry-Perot displacement sensors
- detect via changes in reflectance
- need absolute displacement!
- short cavity: g order _
- max travel less than periodicity
- can use lower coherence source
- how to fabricate micromachined version?
- membrane supports moving mirror
- design for linearity, sensitivity, yield?