Design and modelling of dispersion-engineered rib waveguide for ultra broadband mid-infrared supercontinuum generation

Abstract

We report a dispersion-engineered As₂Se₃ chalcogenide glass rib waveguide structure for ultra broadband mid-infrared supercontinuum generation across molecular ‘fingerprint region’. The proposed rib waveguide structure offers non-linear coefficient as high as 18,250 W⁻¹ km⁻¹ at 2.5 μm. Supercontinuum spectrum spanning 2–15 μm, which not only covers the both atmospheric transparent windows (3–5 μm and 8–13 μm) in the mid-infrared domain but also covers the important molecular ‘fingerprint domain’, is obtained using only 4 mm-long rib waveguide structure. To the best of our knowledge, such broadband mid-infrared supercontinuum spectrum in As₂Se₃-based chalcogenide waveguide geometry is reported for the first time. The proposed design of rib waveguide has potential for robust, integrated and low-cost supercontinuum sources in various applications including frequency comb generation, chemical sensing, food quality control and early cancer diagnostics.

Keywords:

• Non-linear optics
• highly non-linear rib waveguide
• mid-infrared supercontinuum generation

Acknowledgement

The authors gratefully acknowledge the (i) TUN-IND bilateral research project ‘Design, modeling and characterization of highly nonlinear fibers for all-optical high bit-rate network’, funded by Ministry of Higher Education and Scientific Research of Republic of Tunisia and Department of Science and Technology, Govt. of India; and (ii) initiatives and support towards establishment of the ‘TIFAC-Center of Relevance and Excellence’ in Fiber Optics and Optical Communication at Delhi Technological University (Formerly Delhi College of Engineering) Delhi, through the ‘Mission REACH’ program of Technology Vision-2020 of the Government of India.