Ion exchange process for fabrication of waveguide couplers for fiber optic sensor applications

Coupling elements for fiber optic vibration/displacement, backscattering, and backreflecting sensors have been fabricated by placing two separate waveguides on top of each other. The waveguides are fabricated by the Ag+‐Na+ ion exchange using Ag films as ion sources. The ion exchange process is analyzed accurately in one dimension and approximately in two dimensions. The design considerations of the couplers and the properties of the fabricated waveguides are presented.