Abstract

Future optical networks are envisioned to be dynamically reconfigurable - optical channels are added/dropped or cross-connected directly in the optical layer using wavelength-division-multiplexing technology. However, for the efficient operation and maintenance of these networks, it is essential to monitor various parameters including the channel power, optical frequency, OSNR, Q-parameter, and optical path, etc [1]. In this paper, we will review the current status of these monitoring techniques with an emphasis on the OSNR monitoring techniques.