A method for producing a Bragg grating in an optical waveguide device such
as an optical fiber. The optical fiber is exposed to a UV source through
a phase mask and this produces a Bragg grating on the fiber. The grating
on the fiber is overexposed such that the gratings are stronger than
desired. The fiber is then annealed to stabilize the gratings left
behind. The gratings left behind are still stronger than desired. The
fiber is then exposed to a point source laser that reduces the index
change for selected portions. This trims the existing grating to result
in the desired grating strength.