Abstract

In fibre optic transmission systems quadratic dispersion compensation may be achieved with dispersion profiling schemes using fibers of differing dispersions [1], Since the first observation of photo-induced refractive index changes in optical fibers, and the subsequent capability of manufacturing in-fiber Bragg gratings [2] there has been much interest in application of such gratings for dispersion compensation, particularly in fibre optic transmission systems. It has been shown that a linearly chirped Bragg grating used in reflection has particular potential in this area as it has (approximately) a constant dispersion over band widths sufficient to support ultra-short pulses [3]. Such gratings have been demonstrated in a variety of dispersion compensation and pulse compression applications [4, 5]. The problem of cubic disprsion compensation is not easily addressed with fibre dispersion profiling schemes as the cubic dispersion in silica is always positive at communication wavelengths. In this paper we show that both quadratic and cubic dispersion compensation may be achieved using practical quadratically chirped gratings. We derive the design equations for such gratings, give some particular design examples and discuss some of the issues involved with using them as dispersion compensation elements.

© 1995 Optical Society of America