Optimised wavelength-set multi-stage broadband access network employing arrayed-waveguide grating routers

We present a novel 3-stage multi-Gb/s switched ATM access architecture, which requires only 24 wavelengths, spaced by 1.6 nm to route to up to 6912 customers. A multi-dimensional bi-directional addressing strategy, based on spatial, wavelength and temporal multiplexing, is adopted, by exploiting the functionality of cascaded programmable and passive arrayed-waveguide gratings (AWGs). Symmetric upstream and downstream bandwidths are enabled by taking advantage of the optical reciprocity of input and output AWG ports, and their cyclic-shifting properties. The outside-plant consists of only passive, temperature-insensitive components, and the requirement for stable and accurately-defined wavelength sources is avoided, so reducing overall costs. The architecture maps onto 99% of current UK network topology, and allows an elegant evolutionary path from current passive optical networks (PONs)