Method for forming distributed bragg reflectors in optical media.

摘要

The method involves exposure to an interference pattern formed by overlapping beams of actinic radiation. When Bragg gratings are formed according to methods of the prior art, these gratings tend to exhibit reflectivity spectra having, in addition to a central peak, a generally undesirable series of subsidiary peaks. These subsidiary peaks are caused by a wave interference effect. The inventive method modifies or eliminates the subsidiary peaks by spatially modulating the average refractive index of the grating, or by spatially modulating the grating period.