Design and cost performance of the multistage WDM-PON access networks

The advantages of employing passive optical architectures in the access net work have been largely recognized. Particularly, recent developments in opt ical technologies have made the realization of wavelength division multiple xing passive optical networks (WDM PON's) feasible and cost-effective. Thes e networks are more future-proof than conventional PON's, thanks to their i ntrinsic optical transparency and their extremely high transmission capacit y. A very useful optical routing device, called Waveguide Grating Router, i s the basic building-block of new PON architectures capable of connecting a large number of users or to improve the use of the optical bandwidth. In t his paper, we analyze the connectivity of WDM PON's composed of multiple st ages of WGR devices. A design tool is also presented which is able to easil y evaluate the connectivity functions of complex WDM PON's, The feasibility of these architectures is discussed by considering the costs and the techn ological limitations on the optical components.