The transmission and reflection spectrum of the coupled-waveguide Bragg-reflection filter are computed by a new method. The filter is based on the use of a Bragg grating to obtain contradirectional coupling between two dissimilar waveguides. The analysis shows that the tuning range should be similar to that of a simple Bragg grating filter, but with the advantage of having the output separated from the input. This device could also be used as a selective tap in a wavelength-division multiplexing system