Improved method for loss measurements in planar waveguides

A method employing an isosceles prism and a right-angle one is developed for loss measurement in planar waveguides. During the measuring process, the isosceles prism is fixed and the right-angle prism fixed on the waveguide slides by following the waveguide. Only by adjusting the gap thickness we can realize the loss measurement in planar waveguides. The method is demonstrated with an Ag/Na ion-exchanged waveguide fabricated on BK7 glass from AgNO3AgNO3 melt diluted with NaNO3NaNO3 (mass ratio 1:9), with the condition of 4 h and 335∘C. The experimental results show that the method has the advantages on convenient operation, accurate results and no required end polishing.