Experimental demonstration of bidirectional light transfer in adiabatic waveguide structures

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Waveguide Theory

Background:

• Conventional adiabatic three-waveguide couplers are limited to unidirectional light transfer.
• Existing designs often mimic the stimulated Raman adiabatic passage (STIRAP) process, restricting functionality.

Purpose of the Study:

• To propose and demonstrate a novel optical integrated structure for bidirectional light transfer.
• To overcome the limitations of unidirectional couplers in integrated optics.

Main Methods:

• Design of an N-shaped geometry for three adiabatically coupled waveguides.
• Experimental demonstration of light transfer dynamics.
• Analysis of coupling mechanisms (intuitive and counter-intuitive).

Main Results:

• Achieved complete bidirectional light transfer between two waveguides.
• Demonstrated functionality over a wide wavelength range.
• Showcased more efficient and robust light transfer via intuitive coupling compared to counter-intuitive coupling.

Conclusions:

• The proposed N-shaped waveguide structure enables efficient, robust, and bidirectional light transfer.
• This novel design offers advantages over conventional unidirectional couplers for integrated photonic applications.