中国物理B ›› 2020, Vol. 29 ›› Issue (1): 14206-014206.doi: 10.1088/1674-1056/ab5783

• ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS • 上一篇    下一篇

Unitary transformation of general nonoverlapping-image multimode interference couplers with any input and output ports

Ze-Zheng Li(李泽正), Wei-Hua Han(韩伟华), Zhi-Yong Li(李智勇)   

  1. 1 College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100049, China;
    2 State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
  • 收稿日期:2019-08-25 修回日期:2019-09-23 出版日期:2020-01-05 发布日期:2020-01-05
  • 通讯作者: Zhi-Yong Li E-mail:lizhy@semi.ac.cn
  • 基金资助:
    Project supported by the National Key Research and Development Program of China (Grant No. 2018YFB2200202) and the National Natural Science Foundation of China (Grant No. 61804148).

Unitary transformation of general nonoverlapping-image multimode interference couplers with any input and output ports

Ze-Zheng Li(李泽正)1,2, Wei-Hua Han(韩伟华)2, Zhi-Yong Li(李智勇)2   

  1. 1 College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100049, China;
    2 State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
  • Received:2019-08-25 Revised:2019-09-23 Online:2020-01-05 Published:2020-01-05
  • Contact: Zhi-Yong Li E-mail:lizhy@semi.ac.cn
  • Supported by:
    Project supported by the National Key Research and Development Program of China (Grant No. 2018YFB2200202) and the National Natural Science Foundation of China (Grant No. 61804148).

摘要: An explanation of optical unitary transformation is presented for general nonoverlapping-image multimode interference (MMI) couplers with any number of input and output ports. The light transformation in the MMI coupler can be considered as an optical field matrix acting on an input light column vector. We investigate the general phase principle of output light image. The complete proof of nonoverlapping-image MMI coupler's optical unitarity along with the phase analysis of matrix element is provided. Based on a two-dimensional finite-difference time-domain (2D-FDTD) simulation, the unitary transformation is obtained for a 4×4 nonoverlapping-image MMI coupler within a deviation of 4×10-2 for orthogonal invariance and 8×10-2 for transvection invariance in the C-band spectral range. A compact 1×4 splitter based on cascaded MMI coupler is proposed, showing a phase deviation less than 5.4° while maintaining a low-loss performance in C-band spectra.

关键词: multimode interference coupler, optical unitary transformation, integrated photonics

Abstract: An explanation of optical unitary transformation is presented for general nonoverlapping-image multimode interference (MMI) couplers with any number of input and output ports. The light transformation in the MMI coupler can be considered as an optical field matrix acting on an input light column vector. We investigate the general phase principle of output light image. The complete proof of nonoverlapping-image MMI coupler's optical unitarity along with the phase analysis of matrix element is provided. Based on a two-dimensional finite-difference time-domain (2D-FDTD) simulation, the unitary transformation is obtained for a 4×4 nonoverlapping-image MMI coupler within a deviation of 4×10-2 for orthogonal invariance and 8×10-2 for transvection invariance in the C-band spectral range. A compact 1×4 splitter based on cascaded MMI coupler is proposed, showing a phase deviation less than 5.4° while maintaining a low-loss performance in C-band spectra.

Key words: multimode interference coupler, optical unitary transformation, integrated photonics

中图分类号:  (Optical communication systems, multiplexers, and demultiplexers?)

  • 42.79.Sz
42.82.-m (Integrated optics) 42.82.Et (Waveguides, couplers, and arrays)