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112 orbital angular momentum modes amplification based on a 7RC-EDF with low differential mode gain
Optics Letters
|December 23, 2022
Summary
Researchers amplified 112 orbital angular momentum (OAM) modes using a novel 7-ring-core erbium-doped fiber (7RC-EDF). This fiber significantly reduced differential mode gain (DMG), paving the way for high-density OAM multiplexed transmission.
Area of Science:
- Optical Communications
- Photonics
- Fiber Optics
Background:
- Orbital angular momentum (OAM) multiplexing offers high spectral efficiency for optical communication systems.
- Achieving low differential mode gain (DMG) across multiple OAM modes is crucial for practical implementation.
- Existing fiber designs often struggle to manage DMG effectively in multi-mode amplification.
Purpose of the Study:
- To demonstrate the amplification of 112 orbital angular momentum (OAM) modes using a specially designed 7-ring-core erbium-doped fiber (7RC-EDF).
- To effectively reduce the differential mode gain (DMG) for all intra-core OAM modes within the 7RC-EDF.
- To investigate the potential of this 7RC-EDF for long-haul, high-density OAM multiplexed transmission.
Main Methods:
- Fabrication of a novel 7-ring-core erbium-doped fiber (7RC-EDF).
- Utilizing a designed ring-core structure with trench assistance to enhance overlap between signal and pump modes, suppressing intra-core DMG.
- Implementing a core-pump configuration with optimized pump power for controlling inter-core differential gain.
- Experimentally optimizing pump power for each core to achieve low DMG across 112 OAM modes.
Main Results:
- Successfully amplified 112 orbital angular momentum (OAM) modes.
- Achieved a record low differential mode gain (DMG) of 2.8 dB across all 112 OAM modes (16 OAM modes per core in the 7 cores).
- Demonstrated effective suppression of intra-core DMG through optimized mode overlap and inter-core DMG control via pump power configuration.
- Obtained results at a wavelength of 1550 nm.
Conclusions:
- The designed 7RC-EDF effectively amplifies a large number of OAM modes while significantly reducing differential mode gain.
- The achieved low DMG performance is attributed to the unique fiber structure and optimized pumping scheme.
- This advancement holds significant promise for enabling long-haul, high-density OAM multiplexed optical communication systems.
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