We show analytically that, at a critical point where the effective refractive index of a mode coincides with the bulk index of a substrate region, for certain graded-index planar waveguides there exists a family of bound modes with algebraic (power-law) tails in the evanescent field.
© 1995 Optical Society of America
K. Hayata and M. Koshiba, "Algebraically decaying modes of dielectric planar waveguides," Opt. Lett. 20, 1131-1132 (1995)