Modelling, design and optimization of compact taper and gratings for mode coupling to SOI waveguides at C-band

• Published in: Journal of modern optics Vol. 67; no. 12; pp. 1112 - 1119
• Main Authors: Muniswamy, Venkatesha, Krishnaswamy, Narayan
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 11.07.2020; Taylor & Francis Ltd
• Subjects: C band; Compact taper; Coupled modes; Couplers; Coupling; coupling loss; Design optimization; gratings; Infrared radiation; Integrated circuits; Optical waveguides; SOI (semiconductors); Tapering; Transmission efficiency; Transmittance
• ISSN: 0950-0340; 1362-3044
• DOI: 10.1080/09500340.2020.1810797

In this work, the design and optimization of compact taper is presented to enable coupling of infrared light in the C-band with the nano-photonic silicon-on-insulator (SOI) integrated optical waveguide. The proposed compact taper results in ∼96% transmission efficiency for the taper length of ∼5 µm and ∼99.5% transmission efficiency for the taper length of 10 µm. The use of the proposed compact taper significantly reduces the foot print of optical coupler (grating and proposed compact taper) to (10 × 5) µm 2 with ∼96% transmittance and (10 × 10) µm 2 with ∼99.5% transmittance. The end-to-end coupling loss is less than 0.01 dB in the C-band. The compact taper along with grating presented in this work can be used as an efficient optical coupler for mode coupling from fibre to SOI single-mode optical waveguide in high density optical integrated circuits operating at 1550 nm.