Korean Journal of Optics and Photonics (한국광학회지)

Optical Society of Korea (한국광학회)
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CPW travelling-wave electrodes, Mach-Zehnder type Ti:LiNbO3 optical modulator

CPW 진행파 전극, M-Z형 Ti:LiNbO3 광 변조기

  • Pi Joong-Ho (Dept. of Electronics Engineering, The University of Seoul) ;
  • Jung Eun-Joo (Dept. of Electronics Engineering, The University of Seoul) ;
  • Choi Jung-Sung (Dept. of Electronics Engineering, The University of Seoul) ;
  • Kim Chang-Min (Dept. of Electronics Engineering, The University of Seoul)
  • 피중호 (서울시립대학교 전자전기컴퓨터공학부) ;
  • 정은주 (서울시립대학교 전자전기컴퓨터공학부) ;
  • 최정성 (서울시립대학교 전자전기컴퓨터공학부) ;
  • 김창민 (서울시립대학교 전자전기컴퓨터공학부)
  • Published : 2004.10.01
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Abstract

We have fabricated a LiNbO$_3$ travelling-wave optical modulator. The travelling-wave modulator consisted of M-Z(Mach-Zehnder) interferometer and CPW(Coplanar Waveguide) travelling-wave electrodes. Design of CPW electrodes were performed by SOR(Successive Over Relaxation) to obtain the conditions of Microwave effective index and impedance matching. The fabricated modulator had -3.2 dB insertion loss, and S$_{11}$ below -15 dB up to 12 GHz, S$_{21}$ better than -3 dB upto 7 GHz. It turned out that the optical response showed the 3 dB bandwidth of above 12 GHz.

Mach-Zehnder 간섭기와 CPW 진행파 전극을 이용한 외부 광변조기를 제작하였다. 유한차분법(FDM)을 이용하여 단일모드를 갖는 Ti:LiNbO$_3$ 광도파를 설계하고 이를 기반으로 M-Z 간섭기를 설계하였다. 또한 도파광과 MW간의 위상속도를 정합시키고 MW의 특성임피던스를 50Ω으로 맞추기 위하여, CPW 전극의 입$.$출력단 및 변조영역을 반복이완법(SOR)으로 수치해석 하였다. 제작된 소자의 삽입손실은 -3.2dB 정도였고, CPW 전극의 S$_{11}$은 12 GHz 이하의 주파수에서 -15 dB이하를 유지하였으며, S$_{21}$은 7 GHz까지 -3dB 이상을 나타내었다. 주파수 응답 측정 결과, 12 GHz에서 3 dB 변조대역폭을 갖는 것으로 측정되었다.

Keywords

References

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