Novel fiber optic sensors comprising modans--diffractive optical elements matched to the modes--are described. Design, development, and creation of transmittance-type modans based on a variety of microrelief formation technologies including grey-level photoresists, bleaching, and microlithography are reported. The first experimental results of the pressure fiber sensor exploiting modans are presented. The axial-symmetric Gauss- Laguerre modes numbered (0,0), (1,0), (2,0) were excited by input modans and detected by output modans. The modal output power under the known input was being measured versus the fiber microbends induced by 0-150 micrometers displacements of the diaphragm. Sensitivity increase of the fiber sensor was achieved due to mode selection with computer-generated optical elements. The ability of multirange operation of the single sensor under the switching mode's number has been experimentally confirmed.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.