Wavelength-Tunable Vortex Beam Emitter Based on Silicon Micro-Ring with PN Depletion Diode.

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Semiconductor Devices

Background:

• Optical vortices are crucial for telecommunications, biochemical sensing, and advanced applications.
• Existing optical vortex emitters lack efficient spectral tunability, limiting their use in dynamic sensing and communication systems.
• Fiber Bragg gratings (FBGs) are widely used in sensing, but their accuracy can be improved with tunable spectral components.

Purpose of the Study:

• To propose and numerically model a novel wavelength-tunable integrated vortex beam emitter.
• To demonstrate the device's ability to shift resonance wavelengths while maintaining vortex beam properties.
• To explore the potential of this tunable emitter for enhancing sensor accuracy and enabling high-speed optical modulation.

Main Methods:

• Design of a silicon-on-insulator (SOI) based microring resonator with an integrated PN-depletion diode and a grating coupler.
• Utilizing the free plasma dispersion effect for refractive index modulation and wavelength tuning.
• Numerical modeling to verify resonance wavelength shifts and topological charge preservation of the vortex beam.

Main Results:

• Successful demonstration of a wavelength-tunable vortex beam emitter.
• Achieved resonance wavelength shifts by leveraging the free plasma dispersion effect.
• Maintained the topological charge of the emitted vortex beam during spectral tuning.
• Showcased the potential for resonance displacement equal to the free spectral range of the microring resonator.

Conclusions:

• The proposed integrated device offers efficient wavelength tunability for optical vortex generation.
• This technology can significantly enhance the accuracy of sensors, particularly those based on fiber Bragg gratings.
• The device enables ultra-fast orbital angular momentum (de)multiplexing and modulation for advanced optical communication systems.