Channel waveguides with bend compensation for low-loss optical transmission

A method of forming a channel waveguide with a compensated bend section and a straight section comprising a straight-section refractive index cross-sectional profile, the method comprising:

• a) forming in a glass-based substrate a modifying ion-exchanged (IOX) region using a first IOX process that uses a first mask having a first arcuate opening with a first radius of curvature;
• b) forming in the glass-based substrate a waveguide bend IOX region using a second IOX process that uses a second mask having a second arcuate opening with a second radius of curvature, the second IOX process designed to impart a straight-section cross-sectional refractive index profile in the absence of the modifying IOX region, wherein the first and second arcuate openings have substantially the same center of curvature, and the first radius of curvature is less than the second radius of curvature;
• and
• c) wherein the modifying IOX region and the waveguide bend IOX region combine to form a compensated waveguide bend IOX region that defines in the channel waveguide the compensated bend section, which has an amount of optical loss less than if the modifying IOX region were absent.