High-Efficiency and Ultra-Compact Thin-Film Lithium Niobate Phase Modulator Based on a Dual-Noncentered Waveguides Recycling Structure

TY - JOUR

T1 - High-Efficiency and Ultra-Compact Thin-Film Lithium Niobate Phase Modulator Based on a Dual-Noncentered Waveguides Recycling Structure

AU - Huang, Zixuan

AU - Wang, Yuxi

AU - Wang, Bin

AU - Zhang, Weifeng

N1 - Publisher Copyright: © 1983-2012 IEEE.

PY - 2026/5/1

Y1 - 2026/5/1

N2 - Wideband electro-optic phase modulator (PM) serves as a pivotal component in modern photonic systems, enabling critical applications ranging from high-speed optical communication and broadband optical frequency comb (OFC) generation to high-resolution microwave photonic radar imaging. In this work, we propose a high-efficiency and ultra-compact thin-film lithium niobate (TFLN) PM based on a dual-noncentered waveguides recycling structure. In the proposed electro-optic PM, two specially-designed noncentered waveguides are placed within a shared modulation region of the capacitively-loaded travelling wave electrodes (CL-TWEs). By passing the optical signal through the modulation region twice via a loop-back waveguide and optical crossing, the interaction between the optical mode and electrical field is enhanced, thereby significantly boosting the modulation efficiency. The chip is designed, fabricated and evaluated. The experimental results demonstrate that the proposed TFLN PM achieves a low voltage-length product (Vπ·L) of 3.5 V·cm at 11.6 GHz, a low-Vπ bandwidth of 6.2 GHz, a high working frequency up to 46.6 GHz, and an ultra-compact footprint of 0.4×5.5 mm2. By leveraging the fabricated TFLN-PM, tunable OFCs with comb spacings of 9 GHz, 11 GHz and 14 GHz are experimentally generated. The proposed TFLN PM delivers high modulation efficiency, wide operational bandwidth and an ultra-compact footprint, making it a promising candidate for next-generation optical communication and signal processing systems.

AB - Wideband electro-optic phase modulator (PM) serves as a pivotal component in modern photonic systems, enabling critical applications ranging from high-speed optical communication and broadband optical frequency comb (OFC) generation to high-resolution microwave photonic radar imaging. In this work, we propose a high-efficiency and ultra-compact thin-film lithium niobate (TFLN) PM based on a dual-noncentered waveguides recycling structure. In the proposed electro-optic PM, two specially-designed noncentered waveguides are placed within a shared modulation region of the capacitively-loaded travelling wave electrodes (CL-TWEs). By passing the optical signal through the modulation region twice via a loop-back waveguide and optical crossing, the interaction between the optical mode and electrical field is enhanced, thereby significantly boosting the modulation efficiency. The chip is designed, fabricated and evaluated. The experimental results demonstrate that the proposed TFLN PM achieves a low voltage-length product (Vπ·L) of 3.5 V·cm at 11.6 GHz, a low-Vπ bandwidth of 6.2 GHz, a high working frequency up to 46.6 GHz, and an ultra-compact footprint of 0.4×5.5 mm2. By leveraging the fabricated TFLN-PM, tunable OFCs with comb spacings of 9 GHz, 11 GHz and 14 GHz are experimentally generated. The proposed TFLN PM delivers high modulation efficiency, wide operational bandwidth and an ultra-compact footprint, making it a promising candidate for next-generation optical communication and signal processing systems.

KW - Electro-optic phase modulator (PM)

KW - noncentered waveguides

KW - optical frequency comb (OFC)

KW - thin-film lithium niobate (TFLN)

UR - https://www.scopus.com/pages/publications/105030468602

U2 - 10.1109/JLT.2026.3666183

DO - 10.1109/JLT.2026.3666183

M3 - Article

AN - SCOPUS:105030468602

SN - 0733-8724

VL - 44

SP - 4120

EP - 4128

JO - Journal of Lightwave Technology

JF - Journal of Lightwave Technology

IS - 10

ER -