A method is presented for compensating cavity thickness variations in conventional Fabry–Perot devices through the replacement of the input mirror with a holographic mirror, resulting in a self-tuned Fabry–Perot (STFP) device. The technique is suitable for integrating large arrays of electro-optic Fabry–Perot modulators with silicon circuitry. Experimental results of a STFP modulator are presented showing cavity thickness compensation of an electrooptic 9/65/35 bulk lead lanthanum zirconate titanate crystal having thickness variations corresponding to∼6Fabry–Perot fringes in a2.5×2.5mm2area. The compensated modulator used anin siturecorded Fe-doped LiNbO3holographic mirror, and had a uniform backreflection over a2.5×2.5mm2area. ©1997 American Institute of Physics.