Polarized topological invariance frequency conversion on high-fidelity information transfer

Area of Science:

• Optics and Photonics
• Information Technology
• Quantum Information Science

Background:

• Optical vortex-based information networks require cross-band converters to link modules at different wavelengths.
• Traditional methods face distortion due to nonlinear efficiency dependence on orbital angular momentum (OAM).

Purpose of the Study:

• To demonstrate a frequency converter that overcomes OAM-dependent distortion for high-fidelity information transmission.
• To enable cross-platform information transmission in optical networks.

Main Methods:

• Utilizing optical vector vortices with tailored polarization modes as information carriers.
• Employing polarization topology one-to-one mapping for mode identification.
• Implementing sum-frequency generation (SFG) for frequency conversion.

Main Results:

• A simple and flexible frequency converter was demonstrated.
• The converter preserves the topological invariance of polarization.
• Vector vortex-encoded image information was successfully transferred from 1064 nm to 630.9 nm without quality degradation.

Conclusions:

• The developed frequency converter enables high-fidelity information transmission across different wavelength bands.
• This approach addresses limitations of traditional OAM-based methods.
• The technology holds potential for broader applications in optical networks.