25 GHz interleavers with ultra-low chromatic dispersion

Summary form only given. To meet the requirement of next generation systems, passive DWDM components must have the following characteristics, low dispersion, small channel spacing, low insertion loss and high isolation. We discuss the origins of chromatic dispersion of interleavers. We present chromatic dispersion of three different 50 GHz types of interleavers (a Fourier filter flat-top interleaver and two types similar to the Gires-Tournois interferometer). We show that the intrinsic chromatic dispersion of a interleaver quadruples as its channel spacing is reduced by half. We further present two effective methods for reducing chromatic dispersion of interleavers. Finally, we present the performance of two 25 GHz flat-top interleavers that meet the stringent requirements of 10 Gb/s applications. One interleaver was fabricated using the cascading method and one using the double-pass method.