The ZEMAX optical design program integrates all the tools necessary for conceptualizing, designing, optimizing, analyzing, tolerancing and documenting sequential and nonsequential optical systems.ZEMAX can be used to evaluate systems with components such as GRIN or ball lenses, gratings and other diffractive components, and lenslet arrays. A MEMS structure is also available. Any switching state for the device can be represented. Polarization calculations consider the effects of thin-film coatings, bulk absorption and scatter. The state of the polarization can be calculated at any surface in the system.Birefringent uniaxial crystals can be modeled, calculating the correct phase for any arbitrary orientation of the crystal axis, input polarization state and angle of incidence. The fiber-coupling-efficiency calculation includes the effects of aberrations in the system as well as positional errors of the source or receiver. Optimization based on coupling efficiency also is provided.Using the nonsequential capabilities of ZEMAX, scattered and backreflected energy can be traced to determine potential sources of crosstalk or light leaks. Bulk scatter and absorption can model fiber attenuation.