DSP-Based High Speed Polarization Control System

Polarization Controller (PC) is an indispensable component for the state of polarization (SOP) control in optical communication and optical sensor systems. Fast response speed, high extinction ratio, and small fluctuation with endless reset or reset-free SOP control are the criterion of PC. In this thesis, we focus on the development of a PC system base on the transparent ferroelectric ceramics and realized by DSP embedded system.The main analysis work can be divided into two parts: hardware design and DSP firmware design. Using Ti'2000 series product TMS320F2812, a DSP embedded system is designed for the PC using transparent ferroelectric ceramics. Using the on chip analog to digital (AD) module to get four polarization related simulated voltages from polarization detector and calculate the output of four voltage to control the transparent ferroelectric ceramics to generate extra polarization to compensate the polarization in the fiber. Digital to analog (DA) module is designed using unique DA module to provide accurate and fast response voltage on ferroelectric ceramics.The stimulated anneal algorithm is investigated in detail by computer simulations and the imitation of stimulated anneal algorithm on convergence is discussed. Firstly transplant the algorithm from PC to the DSP embedded system. Then introduce four input data related to Stockes Vectors to get more information and get the exact position of current polarization state on the Poincare's Sphere. The fast control algorithm was then been designed to use the data to realize high speed polarization control.This new algorithm was then been simulated on computer and proved effective by experiments. A large amount of data are use to analyze the process of the given algorithm. According to the simulation and experiement results, a conclution could be formed that at average 10 cycles of control outputs are needed to complete a control process. A comprehensive comparison between the proposed fast location algorithm and the previous stimulated anneal algorithm is implemented to illustrate the improvement owing to the use of the fast location algorithm. Therefore it is evident that the presented fast control algorithm can successfully overcome the shortcomings (e.g., poor convergence and low efficiency) of the stimulated anneal algorithm. Although there are still problems on endless control and the stability, this algorithm revealed a new approach to realize a high speed realtime polarization control.The results presented in this dissertation are helpful to the development of newtype of PC.