Energy efficiency of electronic and optical QAM signal grooming

Abstract

Wavelength grooming technologies when used with power management schemes can reduce the energy consumption of optical networks and increase spectral efficiency. Grooming aggregates multiple tributary lower data rate or lower order modulation format signals into a single higher data rate signal with increased spectral efficiency. At high data rates electronic digital signal processing of multiple advanced modulation format signals limits the net energy efficiency benefits. Optical techniques have received interest recently as an alternative, but require specialized optical components with unique energy requirements. The relative energy consumption of optical processing techniques for grooming, including the impact of power management, is evaluated with respect to conventional electronic processing on quadrature amplitude modulated (QAM) signals. Energy efficiency targets in light of expected efficiency improvement trends are determined as a function of signal baud rate. The impact of finite transmission switching delays for dynamic wavelength operation are shown to reduce the optimum baud rate for optical techniques and incur a large penalty at high baud rates.