Pilot Tone based CD and PMD Monitoring Technique for Photonic Networks

Objectives: This paper aims at evaluation of pilot tone based Chromatic dispersion and Polarization mode dispersion monitoring technique and to find out a suitable solution for simultaneous monitoring of CD and PMD in dynamic optical network. Method: A pilot tone of 2GHz to 8GHz has been send to each channel of a WDM Link for the monitoring of performance degradation of composite signal during the transmission. CD and PMD causes phase shift of LSB and USB of the amplitude modulated pilot tone which results variation of amplitude of the pilot tone. The amplitude of the pilot tome is the parameter by which measurement of different quantities such as optical power, wavelength, OSNR, CD and PMD can be done in a dynamic optical network. Findings: From the various literatures it has been observed that Optical network is switching from static form to dynamic form. Implementation of plug and play devices, adaptive modulation techniques and various dynamic services introduce complexity in photonic network. Due to highly dynamic and heterogeneous nature of optical network, investigation and implementation of appropriate performance monitoring technique is a major challenge for the researchers. This paper presents a pilot tone based method for simultaneous monitoring of CD and PMD. The proposed method is suitable for dynamic optical network and the simulation results shows low frequency pilot tones provides better resolution for both CD and PMD monitoring technique. The simulation result shows that 2GHz pilot tone provides CD measurement range upto 16000ps/nm and PMD DGD value upto 50ps for the tone power variation of -10 to 0dB. Applications: The proposed techniques can be used for simultaneous CD and PMD monitoring of dynamic WDM optical networks.