T-Branch Waveguide Mirror for Multimode Optical Splitter With Arbitrary Power Ratios

• Published in: IEEE journal of quantum electronics Vol. 57; no. 5; pp. 1 - 6
• Main Authors: Zhong, Zhongqiu, Liu, Yingjie, Wang, Shuai, Liu, Yilin, Jin, Hongzhi, Song, Qinghai, Xu, Ke
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.10.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Crosstalk; Geometrical optics; Integrated optics; Mirrors; multimode; Multiplexing; Optical interconnects; Optical reflection; Optical waveguides; Power splitters; Reflection; Reflectivity; Refractive index; splitters; System-on-chip; Waveguides
• ISSN: 0018-9197; 1558-1713
• DOI: 10.1109/JQE.2021.3104851

Mode-division multiplexing is an enabling technique for large-capacity on-chip optical interconnects. Multimode power splitter becomes the subject of interests which is highly desirable. However, challenges still exist for multimode splitter with arbitrary power ratio. Inspired by geometric optics, we demonstrate a series of power splitters based on T-branch waveguide mirrors which consist of subwavelength nanoholes. Arbitrary split ratio can be achieved by modifying the transmittance and reflectance of the waveguide mirrors. The devices can support up to 9 modes from TE 0 -TE 8 . For a proof-of-concept demonstration, we fabricate dual-mode splitters with power ratios of 40:60, 30:70 and 20:80. For both TE 0 and TE 1 modes, the measured excess losses are lower than 0.92 dB, and the crosstalk are all below -14.42 dB within the wavelength range from 1540 to 1580 nm.