R. Zengerle and O. Leminger, ‘Phase-shifted Bragg-grating filters with improved
transmission characteristics,’ J. Lightwave Technol., vol. 13, No.12, (1995), pp. 2354-
The example demonstrates an InP/InGaAsP planar waveguide filter. The design is
based on five gratings and four phase shifts. The uniform, rectangular-shaped
gratings are placed on the top of the waveguide. The phase shift regions of different
length separate the gratings. The phase shifts, provided by the phase shift regions,
are 0.5, 1.5, 2.5, and 3.5 p, at the central wavelength.
The main result is the transmission spectrum. It shows that the properly chosen
locations and magnitudes of the phase shift regions can tailor the spectrum into a
nearly rectangular shape.