Abstract

The concept of rugate filters has been known for almost a decade, where a rugate is a medium with a periodically varying refractive index. The spectral performance of a rugate is the Fourier Transform of its refractive index profile. A sinusoidal refractive index profile results in a single rejection band whose wavelength is determined by the modulation frequency and whose bandwidth and rejection level by the peak to peak refractive index modulation and the number of periods.

© 1992 Optical Society of America