  The supersymmetric (SUSY) structure of coupled-mode equations that describe
scattering of optical waves in one-dimensional Bragg gratings is highlighted.
This property can find applications to the synthesis of special Bragg filters
and distributed-feedback (DFB) optical cavities. In particular, multiple SUSY
(Darboux-Crum) transformations can be used to synthesize DFB filters with any
desired number of resonances at target frequencies. As an example, we describe
the design of a DFB structure with a set of equally-spaced resonances, i.e. a
frequency comb transmission filter.
