Demonstration of quasi-contentionless flexible ROADM based on a multiport WXC

Colorless, directionless, and contentionless (CDC) are considered to be three important features for next-generation reconfigurable optical add/drop multiplexer (ROADM) nodes. However, CDC-ROADMs have not been widely deployed due to their relatively higher cost and complexity. In this paper, a compact and multiport wavelength cross connect (WXC) is proposed and demonstrated. Based on the developed WXC, we introduce two novel quasi-contentionless ROADM architectures, which provide considerable reduction of traffic blocking ratio when compared with colorless/directionless (CD)-ROADM architectures. Meanwhile, compared to conventional CDC-ROADMs, the proposed architectures show advantages on cost, intrafiber connection, and system complexity. Experiments are carried out to demonstrate the ability to add/drop two or more identical wavelengths simultaneously in a static network and the flex-grid wavelength routing characteristic of the proposed ROADM nodes. These results indicate that the proposed ROADM solution is a practical and promising trade-off for future elastic optical networks.