Totally internally reflecting thin-film optical cavities.
Thin-film optical cavities formed by optical waveguides in which end faces are parallel, optically smooth, and perpendicular to waveguide surfaces are analyzed for the possibility of total internal reflection of waveguide mode ray components at the end faces. Conditions for the occurrence of this phenomena in various modes are derived and evaluated for GaAs waveguides using dispersion relations. A refractive index difference between waveguide and surrounding media of at least 4% for GaAs is necessary before total reflection at the end faces can occur. is nearly always expected. For such differences, total reflection in single mode GaAs waveguide is nearly always expected.
Boyd
J T
JT