Architecture and performance evaluation of fiber-granularity routing networks with supplemental grooming by wavelength conversion

Abstract

Fiber-granularity routing networks that adopt wavelength-granularity add/drop and a limited number of wavelength converters are proposed. The express parts of nodes can be optical switches, used as fiber cross-connects (FXCs), as they offer low-cost scaling. However, FXCs cannot route optical signals on a wavelength basis, unlike present wavelength cross-connects (WXCs). This routing restriction degrades the statistical multiplexing effect and decreases fiber utilization efficiency. The restriction is slightly relaxed by the use of wavelength-granularity add/drop operations; however, our numerical simulations show that the degradation can reach around 50% when the number of optical paths in a fiber is 25. This substantial degradation is cost-effectively alleviated by introducing wavelength/optical path grooming with a limited number of wavelength converters, which enhances routing flexibility. Numerical simulations show that our network architecture improves routing performance by 86% compared to fiber-granularity routing networks without wavelength converters, and the performance deterioration relative to present WXC-based networks is suppressed to ∼14%.