The well known moire pressure sensor, where one grating is fixed and the other moves with the load, is improved by taking in account the influence of partial coherence effects. Introduction of a specified air gap between the two gratings diminishes drastically perturbations due to parasitical vibrations of mechanical creeping. Use of optical fibers allows a local pure optical measure.
"Pressure Sensors Based On Incoherent Diffraction Effect", Proc. SPIE 0952, Laser Technologies in Industry, (16 January 1988); doi: 10.1117/12.968862; https://doi.org/10.1117/12.968862