The performances of optomechatronic systems are generally characterized by optical imaging phenomena and the proper operation is fundamentally affected by changes of the relative geometry caused by thermal influences, mechanical displacements and vibrations. Extrinsic and intrinsic disturbances can be compensated by active control of optical elements like lenses, diffraction gratings or laser sources. In the context of system design and performance analysis tasks it is big challenge to model and simulate the coupled optomechatronic behavior including closed-loop control and disturbances properly on a representative level. A promising approach is the integration of diffractive optics models in the well established physical object oriented modeling environment Modelica, which offers already a broad support of multi-domain libraries, e.g. electrical, mechanical and thermal. The current paper describes the basic modeling requirements for diffractive optical components and discusses the solution for a computationally efficient implementation of two-dimensional spatial optical interfaces and components for Modelica-based simulation environments. The basic diffractive optical functionality in Modelica is shown by simulation results of a basic Fourier system and a MEMS Micro Mirror Array.