A variant of the re-circulating loop apparatus to experimentally investigate transport issues in DWDM optical mesh networks

A re-circulating loop apparatus is described that would allow one to investigate experimentally issues in dense wavelength division multiplexed (DWDM) optical mesh networks. The configuration is a small variation of the traditional re-circulating loop, with a multi-degree wavelength selective switching (WSS) device as a key element. Amplified links before and after the WSS allow for diverse routing. Addition of a "refresh" switching feature allows selected wavelength channels to be dropped and re-injected as "fresh" channels at points downstream of the propagating channels. The apparatus allows study of transport of channels under diverse outside plant, and a mix of history, dispersion maps, power spectrum, and data rates.