Programmable on-chip nonlinear photonics

Area of Science:

• Photonics and nonlinear optics
• Quantum and classical technologies
• Materials science

Background:

• Nonlinear optical devices are crucial for photonic technologies but typically have fixed functionality after fabrication.
• This inflexibility limits their application in dynamic scenarios.
• Existing devices lack reconfigurability, hindering advancements in adaptive optical systems.

Purpose of the Study:

• To present a novel photonic device with programmable nonlinear optical functionality.
• To demonstrate arbitrary reconfigurable two-dimensional nonlinear distributions.
• To overcome the limitations of fixed-function nonlinear optical devices.

Main Methods:

• Utilized electric-field-induced second-order nonlinear susceptibility (χ(2)) in an optical slab waveguide.
• Engineered programmability via massively parallel control of electric fields using a photoconductive layer and optical programming.
• Demonstrated spectral, spatial, and spatio-spectral engineering of second-harmonic generation (SHG).

Main Results:

• Achieved an arbitrarily reconfigurable two-dimensional distribution of χ(2) nonlinearity.
• Demonstrated in-situ inverse design of quasi-phase-matching grating structures.
• Showcased real-time feedback for compensating operational and environmental fluctuations.

Conclusions:

• The developed device breaks the conventional one-device-one-function paradigm in nonlinear optics.
• Programmable nonlinear optics enables applications requiring fast device reconfigurability.
• Potential applications include programmable quantum gates, adaptive optical signal processing, and advanced sensing.