Synchronous multi-wavelength mode decomposition in few-mode fiber using multi-modal ptychography

Area of Science:

• Optical communications
• Fiber optics engineering
• Wavefront sensing

Background:

• Space-division and wavelength-division multiplexing demand precise multiwavelength modal analysis in few-mode fibers.
• Existing single-wavelength techniques struggle with spectral mixing and wavelength-dependent distortions.

Purpose of the Study:

• To develop and demonstrate a method for synchronous multiwavelength mode decomposition in few-mode fibers.
• To overcome limitations of single-wavelength characterization for advanced multiplexing schemes.

Main Methods:

• Experimental demonstration of a synchronous multiwavelength multimodal ptychographic iterative engine (SMW-MM-PIE).
• Utilized a static imaging system for a single acquisition without realignment.
• Integrated spectral decoupling, digital refocusing, scale compensation, and phase-guided registration.

Main Results:

• Successfully reconstructed complex optical fields at four wavelengths simultaneously.
• Achieved intensity correlation coefficients above 0.97 with LP-basis projections for up to 21 modes.
• Demonstrated agreement with single-wavelength results under identical excitation.

Conclusions:

• The SMW-MM-PIE method provides accurate, synchronous multiwavelength modal characterization for few-mode fibers.
• This technique enhances capabilities for space-division and wavelength-division multiplexing.
• Offers a robust solution for complex modal analysis in optical communication systems.