Enhancing multi-plane light conversion orbital angular momentum multiplexer performance via error analysis.

Area of Science:

• Optics and Photonics
• Optical Communications
• Metamaterials and Nanophotonics

Background:

• Orbital angular momentum (OAM) multiplexing is crucial for increasing optical communication capacity.
• Multi-plane light conversion (MPLC) offers a method for generating and manipulating OAM states.
• Fabrication imperfections in MPLC devices can impact their performance.

Purpose of the Study:

• To present a novel MPLC-based OAM multiplexing apparatus.
• To investigate the impact of fabrication errors (misalignment, etching inaccuracies) on MPLC device performance.
• To demonstrate the practical application of MPLC OAM devices in optical communication systems.

Main Methods:

• Utilized a four-phase-plane MPLC apparatus for OAM generation (topological charges l=0 to ±3).
• Employed a spatial light modulator to analyze the effects of misalignment and etching errors.
• Fabricated MPLC devices with varying etching depths (0-775 nm) on a glass substrate.
• Conducted optical communication experiments transmitting 10 Gbit/s OOK signals over 5 km of few-mode fiber.

Main Results:

• Achieved OAM multiplexing/demultiplexing crosstalk below -20 dB and -18 dB, respectively.
• Reported insertion loss of less than 7 dB for the generated OAM mode coupled to few-mode fiber.
• Successfully demonstrated multiplexing of three OAM channels carrying 10 Gbit/s OOK signals over 5 km of few-mode fiber using two MPLC devices.

Conclusions:

• The developed MPLC-based OAM multiplexing device exhibits excellent performance characteristics.
• The study provides valuable insights into mitigating fabrication errors for improved MPLC device manufacturing.
• MPLC OAM devices show significant potential for enhancing future optical communication networks.