Korean Journal of Optics and Photonics (한국광학회지)

Optical Society of Korea (한국광학회)
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High Efficiency Tapered Waveguide Antenna for End-fire Optical Phased Array Device

종단방출형 광위상배열 장치를 위한 고효율 안테나

  • Byeongchan Park (Advanced Photonics Research Institute, Gwangju Institute of Science and Technology) ;
  • Nan Ei Yu (Advanced Photonics Research Institute, Gwangju Institute of Science and Technology)
  • 박병찬 (광주과학기술원 고등광기술연구소) ;
  • 유난이 (광주과학기술원 고등광기술연구소)
  • Received : 2023.09.25
  • Accepted : 2023.11.17
  • Published : 2023.12.25
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Abstract

The optical signal injected into an end-fire optical phased array propagates along the waveguides inside the device and is emitted from the edge of the antenna. In general, reflection and scattering occur at the boundary, thereby reducing the emission efficiency of the optical signal. In this article, we propose a silicon nitride (Si3N4) tapered waveguide antenna structure whose width is tapered toward the emitting edge, achieving high emission efficiency operating at the 1,550 nm wavelength. The Si3N4 tapered waveguide antenna was numerically designed using the 3D finite-difference time-domain method. The optical signal emission efficiency increased from 78% to 96.3%, while reflectance decreased from 22% to 3.7% compared with the untapered waveguide antenna counterpart. This result will not only boost the optical signal intensity but also mitigate optical noise resulting from back reflection along the waveguide in the end-fire optical phased array device.

종단방출형 광위상배열장치에 주입된 광신호는 장치 내부의 도파로를 따라서 전파되어 안테나 끝단에서 외부로 방출되는데 이 경계면에서 반사와 산란이 발생하여 광신호의 방출효율이 감소하게 된다. 본 연구에서는 이 방출효율을 증가시키기 위하여 끝단으로 갈수록 폭이 가늘어지는 도파관 안테나를 연구하였다. 도파로는 폭이 2 ㎛, 높이가 0.5 ㎛인 실리콘 나이트라이드를 고려하였으며, 도파로의 끝단을 폭이 가늘어지는 도파관 안테나 구조로 변경한 결과 신호의 방출효율은 78%에서 96.3%까지 증가하고 반사율은 22%에서 3.7%까지 감소하는 것을 확인하였다. 이를 통해 종단방출형 광위상배열장치의 광신호의 세기를 증가시킬 수 있을 뿐만 아니라, 도파로를 따라 반사되는 후방반사에 따른 노이즈의 영향도 줄일 수 있음을 확인하였다.

Keywords

Acknowledgement

한국정보통신산업진흥원 인공지능중심산업융합집적단지조성사업(Grant no. S0315-21-1001-C01); 한국연구재단 중견연구자사업(Grant no. 2021R1A2C100713011); 산업통상자원부 초고난도자율주행모빌리티 인지예측센서기술개발(Grant no. RS-2022-00144310).

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