Study of Polarization Compensation in the WDM/PolSK System

• Main Authors: Hvan-Tine Lee, 李奐亭
• Other Authors: Shyh-Lin Tsao
• Format: Others
• Language: en_US
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/03501364732132114298

碩士 === 國立臺灣師範大學 === 光電科技研究所 === 94 === We use the theorem of resonator to design an asymmetrical resonator, produce a very pure signal mode laser, and make different analysis using this signal mode laser. From modulating the bias voltage of electro-optic switch to changing the state of cavity laser and find the optimum work point to make the experiment of transmission compensated. We utilize PZT to modulate the polarization state of cavity laser and use homemade compensator to compensate. Because the polarization state of the light in the optical fiber is easily changed due to many factors in various environments. Therefore, the ellipticity and DOP also be influenced. But form our experimental results, we know our compensator can reduce the variation of polarization state, is influenced by the environment on the transmission system. And promote the DOP to 84.92%, reduce the variation range of ellipticity to 3.21°. Therefore, we know that our compensator can be applied on various transmission systems and improve the transmission quality, reduce bit error ratio. Our homemade compensator is utilizing the program to scout the orientation of polarization state and feedback control by the program. Then it send out the control signal to correct the polarization station go to the set position of our expectation and let polarization state not changed arbitrarily by the factor of environment, incessantly and influence the transmission quality on the optical transmission system. From study of this experiment, we know that in the process of compensation will cause the transmission delay, so the compensator should not compensate the transmission signal, immediately. In this thesis, we finish the design, measure and analyze of this compensator circuit. From measure result, we should understand the phenomenon of delay while feedback pass through each circuit and some characters of those circuits. We obtain the size of designed circuit (wiring rout) and the length of the data bus should influence the delay time. The first generation compensator eventually ameliorated, we successful reduce the size of our compensator and improve the factors of causing the transmission delay after experimenting repeatedly. However, the feedback speed can be quickened and raise the compensation result after improving those factors. In the future we can let all circuit became to integrated circuit (IC) and applied it on the instrument. Not only simplify the size, but also a great deal of applied it on the high-speed optic network. It can promote the transmission quality and conform to need in the nowadays network.