Advanced Electrode Design for Low-Voltage High-Speed Thin-Film Lithium Niobate Modulators

In this paper, we present a novel transmission line architecture in thin-film lithium niobate (TFLN) platforms to improve the velocity match between the microwave and the optical wave. Compared to conventional coplanar waveguide (CPW), the microwave index (<inline-formula><tex-math notation...

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Bibliographic Details
Main Authors: Xingrui Huang, Yang Liu, Zezheng Li, Huan Guan, Qingquan Wei, Zhiguo Yu, Zhiyong Li
Format: Article
Language:English
Published: IEEE 2021-01-01
Series:IEEE Photonics Journal
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Online Access:https://ieeexplore.ieee.org/document/9378945/
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Summary:In this paper, we present a novel transmission line architecture in thin-film lithium niobate (TFLN) platforms to improve the velocity match between the microwave and the optical wave. Compared to conventional coplanar waveguide (CPW), the microwave index (<inline-formula><tex-math notation="LaTeX">$n_m$</tex-math></inline-formula>) of the proposed slotted electrodes can be optimized from 2.1 to 3 while maintaining the high modulation efficiency and 50-<inline-formula><tex-math notation="LaTeX">$\Omega$</tex-math></inline-formula> impedance match. Equivalent-circuit model analysis and finite-element simulation are performed. The simulated half-wave voltage (V<inline-formula><tex-math notation="LaTeX">$_\pi$</tex-math></inline-formula>) of 1.2&#x00A0;V and E-O modulation bandwidth greater than 80&#x00A0;GHz is obtained for a 2-cm-long modulator. By utilizing the slotted slow-wave electrode, TFLN Mach-Zehnder modulators with CMOS-compatible operating voltage and 3-dB modulation bandwidth greater than 100&#x00A0;GHz are potentialized.
ISSN:1943-0655