A precisely tunable true time delay line (TTDL) based on lithium niobate on insulator waveguide grating is proposed. Utilizing the electro-optic effect of lithium niobate, active tuning of reflected wavelength and time delay can be realized. The numerical simulation results show that, with the optimized grating structure and flexible electrode distribution, wide tuning range and high tuning accuracy of time delay can be achieved by simply controlling the charging position of the electrodes. This TTDL is applied to a tunable bandpass microwave photonic filter (TBMPF), which using PM-IM conversion to suppressed dc signal to achieve bandpass. In the TBMPF, the TTDL plays the role of introducing the dispersion for PM-IM conversion, time delay between the taps and tuning of central frequency. This TTDL can reduce the system complexity and cost of microwave photonic filter.

中文翻译：

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基于 LNOI 波导光栅的可调谐带通微波光子滤波器的真实时间延迟线

提出了一种基于铌酸锂绝缘体波导光栅的精确可调真时间延迟线（TTDL）。利用铌酸锂的电光效应，可以实现反射波长和时延的主动调谐。数值模拟结果表明，优化的光栅结构和灵活的电极分布，可以通过简单控制电极的充电位置来实现宽的调谐范围和高的时间延迟调谐精度。该 TTDL 应用于可调谐带通微波光子滤波器 (TBMPF)，该滤波器使用 PM-IM 转换来抑制直流信号以实现带通。在 TBMPF 中，TTDL 的作用是引入 PM-IM 转换的色散、抽头之间的时间延迟和中心频率的调谐。