Korean Journal of Optics and Photonics (한국광학회지)

Optical Society of Korea (한국광학회)
권호 표지
DOI QR코드

DOI QR Code

Design of Thermo-optic Switch with Low Power Consumption by Electrode Optimization

전극 구조의 최적화를 통한 저전력 열광학 스위치 설계

  • Choi, Chul-Hyun (Optics and Photonics Elite Research Academy (OPERA), School of Information and Communication Engineering, INHA University) ;
  • Kong, Chang-Kyeng (Optics and Photonics Elite Research Academy (OPERA), School of Information and Communication Engineering, INHA University) ;
  • Lee, Min-Woo (Optics and Photonics Elite Research Academy (OPERA), School of Information and Communication Engineering, INHA University) ;
  • Sung, Jun-Ho (Optics and Photonics Elite Research Academy (OPERA), School of Information and Communication Engineering, INHA University) ;
  • Lee, Seung-Gol (Optics and Photonics Elite Research Academy (OPERA), School of Information and Communication Engineering, INHA University) ;
  • Park, Se-Geun (Optics and Photonics Elite Research Academy (OPERA), School of Information and Communication Engineering, INHA University) ;
  • Lee, El-Hang (Optics and Photonics Elite Research Academy (OPERA), School of Information and Communication Engineering, INHA University) ;
  • O, Beom-Hoan (Optics and Photonics Elite Research Academy (OPERA), School of Information and Communication Engineering, INHA University)
  • 최철현 (인하대학교 정보통신공학부, 집적형 광자기술 연구센터) ;
  • 공창경 (인하대학교 정보통신공학부, 집적형 광자기술 연구센터) ;
  • 이민우 (인하대학교 정보통신공학부, 집적형 광자기술 연구센터) ;
  • 성준호 (인하대학교 정보통신공학부, 집적형 광자기술 연구센터) ;
  • 이승걸 (인하대학교 정보통신공학부, 집적형 광자기술 연구센터) ;
  • 박세근 (인하대학교 정보통신공학부, 집적형 광자기술 연구센터) ;
  • 이일항 (인하대학교 정보통신공학부, 집적형 광자기술 연구센터) ;
  • 오범환 (인하대학교 정보통신공학부, 집적형 광자기술 연구센터)
  • Published : 2009.10.25
Download PDF
⟨ Previous Next ⟩

Abstract

We designed a thermo-optic switch based on a directional coupler with not only a high extinction ratio but also significantly low power consumption. The switch operates by using the thermo-optic effect of the polymer which the refractive index changes by heating the electrode. If the electrode is not powered (OFF), the input light will be coupled completely to the other waveguide. When the electrode is powered at a certain level (ON), input light launched into the input waveguide will remain in that waveguide due to the lower index adjusted in the other waveguide. The switch based on the directional coupler was designed using the generalized extinction ratio curve and the lateral shift of the input waveguide. The coupling length is 1,610 ${\mu}m$ and the extinction ratios are -28 and -30 dB for ON and OFF states, respectively. The electrode structures were optimized by thermal analysis. The transported heat into the waveguide is increased, as the electrode width (w) is increased and the center distance between the electrode and the waveguide (d) is decreased. Also, because the heat generated in the electrode affects the other waveguide, the temperature difference between two waveguides is varied as the given w and d. There are specific conditions which have the maximum of the temperature difference. That of the temperature difference is increased as the width and the temperature of the electrode are increased. Especially, when the switch is designed using the condition with the maximum of the temperature difference for switching, the temperature of the electrode can be decreased. We expect this condition will be the novel method for the reduction of the power consumption in a thermo-optic switch.

본 논문에서는 높은 소멸비뿐만 아니라 낮은 파워 소모를 가지는 방향성 결합기 구조의 열광학 스위치를 설계하였다. 설계된 스위치는 전극의 열발생 유무에 따라 폴리머의 굴절률이 변하는 열광학 효과를 이용하여 동작한다. 전극에 파워가 인가되지 않으면(OFF), 입사된 빛은 반대쪽 도파로로 대부분 전이된다. 전극에 일정수준 이상으로 파워가 인가되면(ON), 입력 도파로로 입사된 빛은 반대쪽 도파로의 굴절률이 낮아져 입력 도파로로 진행한다. 방향성 결합기 스위치는 소멸비 일반화 곡선과 입력 도파로의 수평이동 방법을 이용하여 설계되었다. 결합길이는 1,610 ${\mu}m$, on과 off 상태의 소멸비는 각각 -28, -30 dB로 설계되었다. 또한, 본 논문에서 전극 구조는 열분석을 통해 최적화되었다. 전극의 폭(w)이 증가하고 전극과 도파로의 중심간격(d)이 감소할수록 도파로로 전달되는 열은 증가하였다. 전극에서 발생된 열은 반대쪽 도파로에도 영향을 주기 때문에 두 도파로간의 온도차이는 주어진 w와 d에 따라 변한다. 이때, 최대의 온도차이를 보이는 특정한 조건이 존재하였다. 최대 온도차이는 전극의 폭이 넓을수록, 전극의 온도가 높을수록 증가한다. 특히, 스위칭에 필요한 온도차이를 최대 온도차이 조건으로 설계하면 전극의 온도를 낮출 수 있다. 최대 온도차이 조건은 열광학 스위치의 파워소모를 감소시키는 방안이 될 것으로 기대된다.

Keywords

References

  1. R. V. Schmidt and R. C. Alferness, “Directional coupler switches, modulators, and filters using alternating ${\Delta}{\beta}$ techniques,” IEEE Trans. Circuits Syst. 26, 1099-1108 (1979). https://doi.org/10.1109/TCS.1979.1084592
  2. N. Anwar, C. Themistos, B. M. A. Rahman, and K. T. V. Grattan, “Design considerations for an electrooptic directional coupler modulator,” J. Lightwave Technol. 17, 598-605 (1999). https://doi.org/10.1109/50.754789
  3. I. Kiyat, A. Aydinli, and N. Dagli, “A compact siliconon-insulator polarization splitter,” IEEE Photon. Technol. Lett. 17, 100-102 (2005). https://doi.org/10.1109/LPT.2004.838133
  4. H. Lee, G. W. Kim, J. O. Park, S. H. Kim, and Y. C. Chung, “Widely tunable wavelength-selective reflector using polymer waveguide double-ring-resonator add/drop filter and loop-back mirro,” J. Opt. Soc. Korea 12, 157-161 (2008). https://doi.org/10.3807/JOSK.2008.12.3.157
  5. Y. C. Hung, S. K. Kim, H. Fetterman, J. Luo, and A. K.-Y. Jen, “Experimental demonstration of a linearized polymeric directional coupler modulator,” IEEE Photon. Technol. Lett. 19, 1762-1764 (2007). https://doi.org/10.1109/LPT.2007.905661
  6. A. M. Al-hetar, I. Yulianti, A. S. M. Supa'at, and A. B. Mohammad, “Thermo-optic multimode interference switches with air and silicon trenches,” Opt. Comm. 281, 4653-4657 (2008). https://doi.org/10.1016/j.optcom.2008.06.025
  7. S. S. Lee, J. U. Bu, S. Y. Lee, K. C. Song, C. G. Park, and T. S. Kim, “Low-power consumption polymeric attenuator using a micromachined membrane-type waveguide,” IEEE Photon. Technol. Lett. 12, 407-409 (2000). https://doi.org/10.1109/68.839034
  8. D. M. Yeo and S. Y. Shin, “Polymer-silica hybrid 1 ${\times}$ 2 thermooptic switch with low crosstalk,” Opt. Comm. 267, 388-393 (2006). https://doi.org/10.1016/j.optcom.2006.06.075
  9. C. H. Choi, S. R. Park, and B. H. O, “A novel concept for a directional coupler design,” Hankook Kwanghak Hoeji (Korean J. Opt. Photon.) 11, 405-410 (2000).
  10. C. H. Choi, B. H. O, S. G. Lee, S. G. Park, and E. H. Lee, “The generalized characteristics of extinction ratio for a directional coupler and design of compact 1310/1550 nm demultiplexer,” Hankook Kwanghak Hoeji (Korean J. Opt. Photon.) 16, 446-449 (2005). https://doi.org/10.3807/KJOP.2005.16.5.446