Research On Polarization Mode Dispersion Monitoring In Optical Performance Monitoring Of Dynamic Optical Network

With the rapid growth of global broadband traffic, people are seeking both high-capacity and high-bandwidth fiber-optic communication systems urgently. High-speed, dynamic, intelligent all-optical network based on Dense Wavelength Division Multiplexing (DWDM) technology is the development direction of the optical communications in the future and a hot research field currently. Highly desirable features of a future "smart" network include higher robustness, reconfigurability, flexibility, and security. To enable robust and smart operation, the network should be able to:(1) measure its physical state and the quality of the propagating data signals;(2) automaticallydiagnose and repair the failures;(3) take actions before data loss and failure occur;(4) allocateresources, including signal wavelength/power, tunable compensation/equalization, data coding, path determination, and channel bandwidth;(5) change routing tables and redirect traffic based on physicallayer conditions. Therefore, we should monitor the power, optical signal to noise ratio (OSNR), chromatic dispersion (CD), polarization mode dispersion (PMD) and other parameters in the key position, which is called optical performance monitoring (OPM).This paper focuses on PMD and OSNR monitoring. The main work of this paper is as follows:1. An overview of the polarization theory of optical signal is made, including three expression forms about polarized light and the mathematical model of polarization controller. Then I describe the generation of polarization mode dispersion and the principal states of polarization. 2. Three PMD monitoring methods are compared, including methods based on the degree of polarization, radio-frequency (RF) power monitoring methods and methods in electric field, and analyze their advantages and disadvantages.3.A PMD monitoring method based on measuring the frequency of the minimum power of RF spectrum is proposed. The monitoring results demonstrate that our method can monitor first order PMD precisely with low monitoring error in±3ps. In addition, it is insensitive to the OSNR, CD and bitrate. Varying the DGD in the PMF at the receiver, this method has different monitoring range and sensitivity.4.In OSNR monitoring, I make an overview of the methods of OSNR monitoring by polarization. Then I propose a new OSNR monitoring method by the DOP. This method has a large monitoring range and is PMD insensitive.