Inconsistency measurement between two branches of LiNbO3 integrated optic Y-junction

• A technique for completely measuring the inconsistency between the two branches of a Y-junction in static and dynamic temperature is proposed.
• The characteristic parameters of two branches of a Y-junction can be calibrated accurately.
• Optical path tracking method for simplifying the analysis of polarization light transmission in Y-junction and PMFs is presented.
• The proposed technique provides an efficient and conducive way for real-time monitoring and selecting qualified Y-junctions in IFOG applications.

We investigate the inconsistency of the polarization related performance between two branches of a packaged LiNbO3 integrated optic Y-junction. An optical path tracking method is proposed to simplify the description of polarization light transmission behavior in packaged Y-junction. By developing a simple but practical fiber test system based on white light interferometry, the interferograms representing different branches of Y-junction are detected and distinguished accurately. The inconsistencies of performance including not only conventional parameters such as polarization extinction ratio of LiNbO3 chip and crosstalk at the joint points between polarization-maintaining pigtails and chip, but also birefringence of LiNbO3 chip and power ratio of Y-junction are obtained with only one-time measurement. It is analyzed theoretically and verified experimentally for complete parameters of a packaged Y-junction. Besides, the static and dynamic measurement results reveal that performance inconsistency for both branches of Y-junction can be effectively evaluated with high accuracy. The inconsistency investigation is highly beneficial in real-time monitoring the inconsistency between two branches of Y-junction and to filtrate qualified Y-junctions.