A Study of Integrated-Optic Passive Polarization Converter

• Main Authors: Jyuhn-Shyurng Chung, 鐘俊雄
• Other Authors: Tzyy-Jiann Wang
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/90459655801414609268

碩士 === 國立臺北科技大學 === 光電技術研究所 === 91 === The polarization characteristic of integrated-optical devices applied in fiber optic communication systems has tremendous influence on the system output. Therefore, the applications of polarization converter become very crucial in such field. In this thesis, the passive polarization converter based on strain-optic effect in X-cut LiNbO3 substrates has been successfully demonstrated by proton-exchange process on Ni-diffusion straight waveguide. By increasing the proton exchange time, the polarization conversion efficiency at the fixed wavelength can be higher than 80%. The central wavelength of polarization conversion can be tuned by electro-optic and thermal-optic effects, and the maximum conversion efficiency can be as high as 89%. This greatly enhances the possibility of practical utilization. In comparison with the previous studies utilizing the stress caused by the different thermal expansion coefficients of LiNbO3 and SiO2, the proposed devices have the following advantages:(1) adjusting the ion concentration and designing proper structure can efficiently enhance the conversion efficiency; (2) the damage and the propagation loss of the device can be reduced due to the absence of RIE procedure. Besides, the production cost can be reduced because of not using RIE system.