Ion-exchanged binary phase plates for mode multiplexing in graded-index optical fibers

Area of Science:

• Optical Engineering
• Photonics
• Telecommunications

Background:

• Few-mode graded-index optical fibers are crucial for advancing spatial division multiplexing (SDM).
• Multi-region binary phase plates are essential components in SDM schemes utilizing these fibers.

Purpose of the Study:

• To propose and analyze a coupling configuration for mode multiplexing in few-mode graded-index optical fibers.
• To analytically calculate theoretical conversion efficiencies and crosstalk between generated fields and Laguerre-Gaussian modes.

Main Methods:

• Development of a coupling configuration using collimating-focusing graded-index lenses and binary phase plates.
• Analytical and quasi-analytical calculations of conversion efficiencies and crosstalk.
• Fabrication of binary phase plates using ion-exchange technology.
• Optical characterization via beam profilometry.

Main Results:

• Theoretical conversion efficiencies and crosstalk were calculated for Laguerre-Gaussian modes, which represent optical modes in graded-index fibers.
• Illumination conditions and optical characteristics for the binary phase plates were determined.
• Experimental conversion efficiencies closely matched the theoretical predictions.

Conclusions:

• The proposed coupling configuration effectively enables mode multiplexing in few-mode graded-index optical fibers.
• Ion-exchange fabricated binary phase plates demonstrate good performance for mode manipulation.
• The study provides a validated analytical framework for designing and optimizing such optical systems.