We report on the first dispersion study performed on planar Bragg gratings
for WDM systems. The gratings are produced in low-loss single-mode polymeri
c waveguides and have a remarkable amplitude response (reflectivity > 99.99
%, suppressed out-of-band features). The phase response study shows that th
e dispersion that they introduce in a system (<100 ps/nm) is lower than tha
t typical of fiber Bragg gratings.