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

The advantages of employing passive optical architectures in the access network have been largely recognized. Particularly, recent developments in optical technologies have made the realization of wavelength division multiplexing passive optical networks (WDM PONs) feasible and cost-effective. These networks are more future-proof than conventional PONs, thanks to their intrinsic optical transparency and their extremely high transmission capacity. A very useful optical routing device, called waveguide grating router, is 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 this paper, we analyze the connectivity of WDM PONs composed of multiple stages of WGR devices. A design tool is also presented which is able to easily evaluate the connectivity functions of complex WDM PONs. The feasibility of these architectures is discussed by considering the costs and the technological limitations on the optical components.