Non-destructive PMD Monitoring in Live WDM Optical Systems
Project Award Date: 03-01-2006
In-situ monitoring of PMD in live, multi-channel WDM systems will be a key requirement for future dynamic optical networks to ensure the quality of operation. Especially, for some optical links with exceptionally high PMD values, an in-situ monitoring of PMD during operation will help network engineers to determine the impact of PMD and used wavelength bands where PMD is less damaging.
We have recently developed a novel and simpler method to evaluate Differential Group Delay (DGD) in a live optical system. This method utilizes the spectral characteristics of the digital signal carried by each wavelength channel and the PMD monitoring can be performed at the receiver or at an optical node without the need to access the transmitter. This PMD monitoring apparatus is based on the coherent detection and RF signal processing.
We will assemble this system into a portable package and make it user-friendly; therefore, it can be used for field applications to monitor live and traffic-carrying systems. Since a tunable laser is used as the local oscillator, its wavelength can be tuned to any optical channel in a WDM system (C band and L band). By programming the wavelength sweep, we will be able to simultaneously monitor various channels across wavelengths.
Primary Sponsor(s): Sprint/United Management Company