Mode-evolution-based silicon-on-insulator 3 dB coupler using fast quasiadiabatic dynamics

Yung Jr Hung, Zhong Ying Li, Hung Ching Chung, Fu Chieh Liang, Ming Yang Jung, Tzu Hsiang Yen, Shuo Yen Tseng

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


We report a 2 × 2 broadband and fabrication tolerant mode-evolution-based 3 dB coupler based on silicon-on-insulator rib waveguides. The operating principle of the coupler is based on the adiabatic evolution of local eigenmodes. The key element of the device is an adiabatically tapered mode evolution region, which converts two dissimilar waveguides into two identical waveguides. Contrary to conventional designs using a linear taper function where the device adiabaticity is uneven during evolution, we use the fast quasiadiabatic approach to homogenize the adiabaticity of the device, leading to a shortcut to adiabaticity. Devices with an optimized taper region of 26.3 μm are designed and fabricated in a complementary metal-oxide-semiconductor compatible process with 193 nm deep ultraviolet lithography. The measured devices exhibit a broadband 3 dB 0.5 dB splitting within a bandwidth of 100 nm, uniformly across a 200-mm wafer, showing good tolerance against fabrication variations.

Original languageEnglish
Pages (from-to)815-818
Number of pages4
JournalOptics Letters
Issue number4
Publication statusPublished - 2019 Feb 15

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics

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