Performance improvement of bandwidth-flexible reconfigurable optical add/drop multiplexers with wavelength converters

In this paper, we propose a novel bandwidth-flexible reconfigurable optical add/drop multiplexer (ROADM) architecture based on coherent optical-orthogonal frequency division multiplexing (CO-OFDM) technology. The bandwidth-flexible ROADM architecture enables sub-wavelength, superwavelength, and multiple-rate data traffic accommodation in a highly spectrum-efficient manner, thereby providing a fractional bandwidth service. We simulate and compare the blocking performance of bandwidth-flexible ROADM with and without wavelength converters. It is found that wavelength converter could obviously improve the blocking performance of bandwidth-flexible ROADM with different frequency grid. Moreover, the conversion ratios are calculated for different load and channel spacing. Based on the analysis of conversion ratio, we could make an appropriate configuration of wavelength converters in bandwidth-flexible ROADM.