Compact and robust 2 × 2 fast quasi-adiabatic 3-dB couplers on SOI strip waveguides

Yung J. Hung, Chih Hsien Chen, Guan Xun Lu, Fu Chieh Liang, Hung Ching Chung, Shuo Yen Tseng

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


We design and experimentally demonstrate compact and robust fast quasi-adiabatic (FAQUAD) couplers for silicon-on-insulator (SOI) strip waveguides. The mode evolution region of the coupler is optimized by the FAQUAD protocol, achieving shortcuts to adiabatic mode evolution in a short length of 11.7 μm. 3-dB couplers with measured bandwidths (3 dB ± 1 dB) larger than 75 nm over temperature range from 20 °C to 50 °C are designed and fabricated using standard CMOS-compatible optical lithography, with the smallest device footprint of 53.7 × 4 μm2. Devices with longer mode evolution regions are also evaluated by simulations and experiments. 3-dB couplers with a footprint of 87.6 × 4 μm2 show larger than 85 nm bandwidths (3 dB ± 0.5 dB) over the same 30 °C range.

Original languageEnglish
Article number107485
JournalOptics and Laser Technology
Publication statusPublished - 2022 Jan

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering


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