Abstract

Complex filters are required for functions such as gain flattening and side-lobe suppression in wavelength division multiplexed optical communication systems. The phase mask technique for fibre grating production provides a reliable and flexible route to achieve this [1-2]. Side lobes and noise effects caused by sudden changes in the optical geometry along the fibre axis [3] can be largely eliminated by apodising the grating along its axis during UV exposure [4]. We have previously reported the design and fabrication of geometrical apodisation and chirp in electron beam written phase masks [5]. Here, we describe the characteristics of these phase masks with various apodisation functions and the reflection spectra of the resulting fibre gratings.

© 1998 IEEE