Optical drop-add-drop network architecture with centralized multi-carrier light source

Abstract

This letter proposes an optical drop-add-drop network architecture with a centralized multi-carrier light source (C-MCLS) for regional and metro network applications. In the drop-add-drop network, optical carriers generated by the CMCLS are dropped at the source nodes and used for uplink transmission. Data are added to the network after external modulations of the carriers. Data are then dropped at the destination nodes. The reconfigurable optical add/drop multiplexer (ROADM) at each node is not only used to add and drop data, but also to drop carriers, which eliminates the distributed laser diodes needed by the conventional network. Network cost analysis and numerical results show that it offers significantly lower network cost compared to the conventional network if the total number of used wavelengths in the network is large. We evaluate its optical performance through an optical signal-to-noise ratio (OSNR) analysis. We show its applicable network size in terms of fiber span length and the number of nodes under a specified bit error rate (BER) when changing the OSNR of the C-MCLS.