How planar optical waves can be made to climb dielectric steps

Area of Science:

• Photonics
• Integrated Optics
• Waveguide Technology

Background:

• 3-D integrated photonic circuits require efficient methods for vertical optical connections.
• Existing methods often suffer from reflections, radiation losses, or polarization conversion.

Purpose of the Study:

• To present a novel technique for optically connecting guiding layers at different elevations in 3-D integrated photonic circuits.
• To achieve efficient optical power transfer without reflections or radiation losses over large vertical distances.

Main Methods:

• Utilizing step-like folds of high-contrast dielectric slab waveguides.
• Employing oblique wave incidence and fulfilling a resonance condition.
• Applying quasi-analytical simulations with silicon/silica parameters.

Main Results:

• Achieved lossless and reflectionless optical power transfer between vertically separated waveguide layers.
• Demonstrated suppression of radiation losses and polarization conversion for TE waves beyond critical angles.
• Confirmed functionality through rigorous simulations, showing full transmission via resonant states.

Conclusions:

• The proposed method enables efficient vertical optical interconnects in 3-D photonic circuits.
• The technique relies on resonant coupling through waveguide step-folds, analogous to a Fabry-Perot resonator.
• This approach offers versatile configurations for advanced on-chip optical networking.