Nanophotonics (Feb 2024)

Lithium niobate thin film electro-optic modulator

  • Liu Jikun,
  • Qu Lun,
  • Wu Wei,
  • Jin Chunyan,
  • Chen Zhihao,
  • Gu Zhidong,
  • Liu Weiye,
  • Wang Chenxiong,
  • Zheng Dahuai,
  • Liu Hongde,
  • Cai Wei,
  • Ren Mengxin,
  • Xu Jingjun

DOI
https://doi.org/10.1515/nanoph-2023-0865
Journal volume & issue
Vol. 13, no. 8
pp. 1503 – 1508

Abstract

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The linear electro-optic effect offers a valuable means to control light properties via an external electric field. Lithium niobate (LN), with its high electro-optic coefficients and broad optical transparency ranges, stands out as a prominent material for efficient electro-optic modulators. The recent advent of lithium niobate-on-insulator (LNOI) wafers has sparked renewed interest in LN for compact photonic devices. In this study, we present an electro-optic modulator utilizing a thin LN film sandwiched between top and bottom gold (Au) film electrodes, forming a Fabry–Pérot (F–P) resonator. This resonator exhibits spectral resonance shifts under an applied electric field, enabling efficient modulation of reflected light strength. The modulator achieved a 2.3 % modulation amplitude under ±10 V alternating voltage. Our approach not only presents a simpler fabrication process but also offers larger modulation amplitudes compared to previously reported metasurface based LN electro-optic modulators. Our results open up new opportunities for compact electro-optic modulators with applications in beam steering devices, dynamic holograms, and spatial light modulators, and more.

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