Analysis of Nonlinear Distortions for External Optical Modulators

• Main Authors: Jia-Long Hong, 洪嘉龍
• Other Authors: Jau-Ji Jou
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/79104792088647202662

碩士 === 國立高雄應用科技大學 === 電子工程系 === 98 === In high-speed optical fiber transmission systems, the nonlinear distortions of the opto-electrical devices, the optical modulators especially, influence the quality of the transmission signals. Therefore, we investigate the nonlinear distortions of the external optical modulators, and provide the simple and accurate method to analysis them. In this thesis, according to the transfer curves of the optical output versus radio-frequency (RF) input for the electro-absorption modulator (EAM) and the Mach-Zehnder Modulator (MZM), and considering the frequency response, we can drive the harmonic and intermodulation distortion formulas of the modulators. We also compare the calculations by our analysis with the related data by the experiments or references. In the nonlinear distortion analysis of the EAM, the transfer curves of the EAM are obtained from the references. When the input RF amplitude rises or the input RF frequency reduces, the nonlinear distortions of the EAM would increase. The nonlinear distortions are also dependent on the input optical power. In the nonlinear distortion analysis of the MZM, the same trends can be obtained for the experiments and the calculations. The nonlinear distortions of the MZM are dependent on the input RF amplitude, the input RF frequency, and the input optical power. In addition, the spurious free dynamic ranges of the MZM are also analyzed, and the calculation has a good agreement with the experiments.