Lithium Niobate Piezoelectric Actuator-Integrated Fiber Fabry-Pérot Tunable Filter with Ultrahigh Speed and Linearity

Fast-tunable filters play a crucial role in various applications including tunable lasers, high-speed optical communications, microwave photonics, and spectroscopy. However, current fiber Fabry-Pérot tunable filters (FFPTF) predominantly rely on piezoelectric transducers (PZT), which struggle to achieve rapid modulation with high repeatability and accuracy owing to hysteresis and creep effects. In this study, we demonstrate an FFPTF with high linearity (>0.99) and an approximate 1 MHz dynamic tuning frequency in the resonant state using the thickness–shear resonance of a Y-cut 163° lithium niobate (LiNbO₃) sheet. The device exhibited a high overall performance with a finesse of 118 and an insertion loss of 2.54 dB, with well-designed fiber cavity configurations. This study provides a new approach for precise and rapid wavelength manipulation and selection, thereby paving the way for high-speed optical modulation and analyses.