We present a nondestructive experimental method to measure monotonically varying refractive-index profiles of planar waveguides. The technique is a modification of the Lloyd's mirage setup proposed by Allman et al. [Appl. Opt. 33, 1806 (1994)] in order to have a reference phase distribution for the interference pattern. The theoretical calculations have been implemented to account for multiple reflections inside the sample. An application of the method to ion-exchanged glass waveguides is reported.
© 1996 Optical Society of America
Original Manuscript: January 5, 1996
Revised Manuscript: April 15, 1996
Published: November 1, 1996
W. A. Ramadan, E. Fazio, and M. Bertolotti, "Measurement of the refractive-index profile of planar waveguides by the use of a double Lloyd's interferometer," Appl. Opt. 35, 6173-6178 (1996)