STUDY OF LINEAR TAPERED WAVE-GUIDES MADE BY ION-EXCHANGE IN GLASS

The optical propagation in linear tapered waveguides is studied using both the beam propagation method as a non-modal technique and for local normal mode analysis. The comparison between the results obtained by the two techniques gives a good physical understanding of the transient behaviour of the optical field in the taper, which enables the use of the taper as a collimating element in planar integrated optics. For experimental verification, tapered waveguides were formed by K+-Na+ ion exchange in glass. A linear taper with an angle of 0.08-degrees has an output beam of 40-mu-m width with a divergence angle of 1.13-degrees.