钛扩散LiNbO_3相位调制器尾纤偏振串音的白光干涉测量方法

White Light Interferometry for Pigtail Polarization Crosstalk of Ti-Diffused LiNbO_3 Integrated Optic Phase Modulator

提出了一种基于白光干涉原理的钛扩散铌酸锂(LiNbO3)集成光学相位调制器尾纤偏振串音测量方法,分析了白光干涉仪输出干涉信号与集成光学芯片和保偏尾纤对轴角度、偏振器起偏角度之间的关系。仿真结果表明:白光干涉仪输出的干涉包络与相位调制器的耦合点存在一一对应的关系,干涉包络的峰值反映了相位调制器的尾纤偏振串音。利用白光干涉仪对某型钛扩散LiNbO3集成光学相位调制器的尾纤偏振串音进行了实际测试,干涉图样中产生了与耦合点位置对应的干涉峰;常温下其输入、输出尾纤偏振串音分别为-34.5dB和-23.3dB;在-40℃～60℃范围内,尾纤偏振串音随温度升高而减小。实验结果验证了测量方法的可行性。

A new test method for the pigtail polarization crosstalk of the Ti-diffused LiNbO3 integrated optic phase modulator（Ti： LiNbO3 IOPM） is proposed based on the white-light interferometry. The white light interference intensity as a function of the alignment angle between the integrated optic chip and the polarization-maintaining pigtail and the azimuth of the polarizer is theoretically analyzed. It is shown by the digital simulation that the pigtail polarization crosstalk of the IOPM can be obtained by the peaks of the interference envelope associated with the polarization coupling points of the IOPM. The pigtail polarization crosstalk of the Ti： LiNbO3 IOPM is tested by utilizing the white light interferometry, and the apparent interference peaks are exhibited at the polarization coupling points. The input and output pigtail polarization crosstalk are -- 34. 5 dB and -- 23. 3 dB respectively at room temperature, and decrease as the temperature rises from --40 ℃ to 60 ℃. The feasibility of the white light interferometry is verified by the experimental results.