Abstract

The performance of filters having sinusoidal refractive index profiles have been published by various authors¹. In general, these filters have a strong reflection at the design wavelength and offer the promise of no harmonics at any wavelength². Further, these refractive index profiles may be superimposed with each other creating multiple stopbands. Fig. 1 shows the refractive index profile and predicted performance of this type of filter, commonly referred to as a rugate (from the Latin for wrinkled) filter. Presented in this paper is an approach for the design of narrow bandpass filters based on this type of refractive index profile. These filters are suitable for applications which require very narrow passbands.

© 1992 Optical Society of America