Abstract

It is shown that quarterwave matching layers are effective in suppressing rugate side lobes only near the wavelengths for which the matching layers are quarterwave. Quintic matching layers (which are fifth-order polynomial index variations with zero first and second derivatives at each end), on the other hand, are capable of suppressing side lobes over wide wavelength regions. Furthermore, the OD loss due to the index matching can be largely restored by the superposition of rugate cycles on the quintic matching regions. It is also shown that the entire rugate may be impressed upon thick quintics. Such structures have excellent broadband side lobe suppression.

© 1988 Optical Society of America