An integrated multi-THz tunable linear isolator based on electro-optic non-reciprocal strong coupling

Area of Science:

• Photonics
• Integrated Optics
• Materials Science

Background:

• Optical isolators are crucial for laser systems, but existing non-magnetic designs face challenges with sidebands, bandwidth, and practicality.
• Previous approaches often relied on acousto-optic (AO) modulation, with electro-optic (EO) methods yet to achieve strong coupling for improved performance.

Purpose of the Study:

• To demonstrate a novel compact EO optical isolator.
• To achieve the non-reciprocal strong coupling regime using electro-optics for the first time.
• To address limitations of existing isolators, such as sideband generation and tunability.

Main Methods:

• Utilized thin film lithium niobate for device fabrication.
• Implemented a design leveraging non-reciprocal strong coupling between optical modes.
• Achieved spatio-temporal modulation through electro-optic effects.

Main Results:

• Demonstrated the first EO device operating in the non-reciprocal strong coupling regime.
• Achieved a very high isolation figure of merit with linear operation and negligible sideband generation.
• Showcased THz-scale (8 nm) tunability of the isolation band, with potential for multi-THz operation.

Conclusions:

• The developed EO optical isolator overcomes key limitations of previous designs.
• This technology enables practical, high-performance optical isolation with enhanced tunability.
• Represents a significant advancement in integrated photonic devices for laser protection and signal routing.