sci-physics The MIT Photonic-Bands (MPB) package is a program for computing the band structures (dispersion relations) and electromagnetic modes of periodic dielectric structures, on both serial and parallel computers. It was developed by Steven G. Johnson at MIT in the Joannopoulos Ab Initio Physics group. This program computes definite-frequency eigenstates of Maxwell's equations in periodic dielectric structures for arbitrary wavevectors, using fully-vectorial and three-dimensional methods. It is especially designed for the study of photonic crystals (a.k.a. photonic band-gap materials), but is also applicable to many other problems in optics, such as waveguides and resonator systems. (For example, it can solve for the modes of waveguides with arbitrary cross-sections.)