Advancing large-scale thin-film PPLN nonlinear photonics with segmented tunable micro-heaters

• Xiaoting LI, Haochuan Li, zhenzheng wang, Zhaoxi CHEN, Fei Ma, Ke ZHANG, wenzhao sun, and Cheng Wang
• received 12/15/2023; accepted 03/27/2024; posted 03/29/2024; Doc. ID 516180
• Abstract: Thin-film periodically poled lithium niobate (TF-PPLN) devices have recently gained prominence forefficient wavelength conversion processes in both classical and quantum applications. However, thepatterning and poling of TF-PPLN devices today are mostly performed at chip scales, presenting a significantbottleneck for future large-scale nonlinear photonic systems that require the integration of multiplenonlinear components with consistent performance and low cost. Here, we take a pivotal step towards thisgoal by developing a wafer-scale TF-PPLN nonlinear photonic platform, leveraging ultraviolet stepperlithography and an automated poling process. To address the inhomogeneous broadening of the quasiphasematching (QPM) spectrum induced by film thickness variations across the wafer, we propose anddemonstrate segmented thermal optic tuning modules that can precisely adjust and align the QPM peakwavelengths in each section. Using the segmented micro-heaters, we show the successful realignment ofinhomogeneously broadened multi-peak QPM spectra with more than doubled peak second-harmonicgeneration efficiency. The advanced fabrication techniques and segmented tuning architectures presentedherein pave the way for wafer-scale integration of complex functional nonlinear photonic circuits withapplications in quantum information processing, precision sensing and metrology, and low-noise-figureoptical signal amplification.