The influence of the different parameters on the optical bistable behavior of a distributed feedback structure with an intensity-dependent refractive index is studied. Previous work is generalized toward two-dimensional waveguides, showing absorption. A general method is proposed to calculate the coupling coefficients up to a desired accuracy. This method is used to compare the feedback efficiency of sine, rectangular, and trapezoidal grating profiles. The numerical integration routine that was developed allows for the study of combinations of different nonlinear distributed feedback (NLDFB) structures. This is used to do a first investigation on the behavior of NLDFB devices with an aperiodic or nonperfect grating profile.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>