Micromachines (Jul 2021)

Folded Heterogeneous Silicon and Lithium Niobate Mach–Zehnder Modulators with Low Drive Voltage

  • Shihao Sun,
  • Mengyue Xu,
  • Mingbo He,
  • Shengqian Gao,
  • Xian Zhang,
  • Lidan Zhou,
  • Lin Liu,
  • Siyuan Yu,
  • Xinlun Cai

DOI
https://doi.org/10.3390/mi12070823
Journal volume & issue
Vol. 12, no. 7
p. 823

Abstract

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Optical modulators were, are, and will continue to be the underpinning devices for optical transceivers at all levels of the optical networks. Recently, heterogeneously integrated silicon and lithium niobate (Si/LN) optical modulators have demonstrated attractive overall performance in terms of optical loss, drive voltage, and modulation bandwidth. However, due to the moderate Pockels coefficient of lithium niobate, the device length of the Si/LN modulator is still relatively long for low-drive-voltage operation. Here, we report a folded Si/LN Mach–Zehnder modulator consisting of meandering optical waveguides and meandering microwave transmission lines, whose device length is approximately two-fifths of the unfolded counterpart while maintaining the overall performance. The present devices feature a low half-wave voltage of 1.24 V, support data rates up to 128 gigabits per second, and show a device length of less than 9 mm.

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