Narrow-band grating filters for thin-film optical waveguides

Abstract

Criteria and tolerances are discussed for realizing grating filters with bandwidths as narrow as 0.1 Å. Techniques are presented for minimizing the adverse effect of film thickness variations which broaden filter response and raise out of band ripple. Using these techniques a grating filter fabricated on a glass thin‐film waveguide is demonstrated which has 73% reflectivity and a 3‐dB bandwidth of 0.15 Å.