High-fidelity spatial mode transmission through a 1-km-long multimode fiber via vectorial time reversal

Area of Science:

• Optical Communications
• Quantum Information Science
• Photonics

Background:

• Multimode fibers offer high channel capacity for communications.
• Modal crosstalk and polarization mixing limit practical applications of long multimode fibers.

Purpose of the Study:

• To overcome limitations in long multimode fiber communications.
• To demonstrate a novel technique for preserving signal integrity over distance.

Main Methods:

• Developed and experimentally demonstrated a vectorial time reversal technique.
• Digitally pre-shaped wavefront and polarization of signal beam as phase conjugate of a probe beam.
• Utilized an unstabilized 1-km-long fiber.

Main Results:

• Achieved an average modal fidelity above 80% for 210 spatial modes (Laguerre-Gauss and Hermite-Gauss).
• Successfully mitigated modal crosstalk and polarization mixing challenges.
• Demonstrated the feasibility of the technique over a kilometer of fiber.

Conclusions:

• Vectorial time reversal is a viable technique for high-fidelity signal transmission in long multimode fibers.
• This method enables practical and scalable spatial-mode-multiplexed quantum communication protocols.
• Opens possibilities for significantly boosting communication channel capacities.