Bound-state-in-continuum guided modes in a multilayer electro-optically active photonic integrated circuit platform

Area of Science:

• Photonics and Wave Dynamics
• Integrated Optics
• Materials Science

Background:

• Open system interactions cause energy dissipation and decoherence, hindering control of physical systems.
• Bound-states-in-continuum (BICs) offer a method to isolate systems by controlling lossy interactions in wave phenomena.
• Existing engineered BICs for photonic waveguiding are often limited by polarization and geometry.

Purpose of the Study:

• To theoretically and experimentally investigate low-loss BIC photonic waveguiding in a heterogeneous electro-optically active platform.
• To explore selective suppression of coupling to the slab wave continuum for guided modes.
• To demonstrate a practical application of BIC waveguiding in an electro-optic modulator.

Main Methods:

• Theoretical modeling of BIC phenomena in a two-layer integrated photonic structure.
• Experimental fabrication and characterization of a Si3N4 ridge waveguide with an LiNbO3 slab.
• Measurement of a quasi-BIC guided mode for a Mach-Zehnder electro-optic amplitude modulator.

Main Results:

• Selective suppression of slab wave continuum coupling for different polarizations and spatial structures.
• Demonstration of a low-loss, same-polarization quasi-BIC guided mode.
• Successful implementation of a high extinction Mach-Zehnder electro-optic amplitude modulator.

Conclusions:

• BIC waveguiding principles can be broadly applied and systematically explored in integrated photonics.
• The demonstrated platform offers a versatile approach for developing advanced photonic devices like modulators, switches, and filters.
• This research has potential implications for other wave dynamics fields, including microwave and acoustics.