First- and second-order Bragg gratings in single-mode planar waveguides ofchalcogenide glasses

First- and second-order Bragg reflectors at telecommunication wavelength (1 .5 mu m) were fabricated in single-mode monolayer (As2S3) and multilayer (A s-S-Se/As-S) chalcogenide glass (ChG) planar waveguides with near bandgap i llumination using an interferometric technique. Reflectivities as high as 9 0% near 1555 nm, and index modulations up to 3 x 10(-4) were achieved, The volume photodarkening effect is the principal mechanism involved in the for mation of the Bragg gratings.