Multiwavelength narrow linewidth erbium-doped fiber laser based on FP-LDs

Area of Science:

• Photonics
• Laser Physics
• Optical Engineering

Background:

• Erbium-doped fiber lasers (EDFLs) are crucial for various optical applications.
• Homogeneous gain broadening in EDFLs limits multiwavelength operation.
• Controlling wavelength-dependent gain/loss is key to overcoming this limitation.

Purpose of the Study:

• To propose and demonstrate a novel technique for multiwavelength operation in EDFLs.
• To utilize Fabry Pérot laser diodes (FP-LDs) for wavelength selection and gain/loss control.
• To enhance EDFL performance for applications requiring multiple, stable wavelengths.

Main Methods:

• Incorporating two FP-LDs into the EDFL cavity in cascaded and parallel configurations.
• Adjusting FP-LD driving currents to control wavelength-dependent optical gain/loss.
• Employing injection locking of FP-LDs to ensure narrow linewidth output.

Main Results:

• Achieved 16-wavelength operation with cascaded FP-LDs and 20-wavelength operation with parallel FP-LDs.
• Maintained a consistent wavelength spacing of 1.25 nm for all achieved wavelengths.
• Demonstrated low power fluctuation (<0.4 dB) for each operating wavelength.
• Confirmed narrow linewidth (<100 MHz) for the cascaded scheme via injection locking.

Conclusions:

• The proposed FP-LD based technique effectively suppresses gain competition in EDFLs.
• This method enables stable, multiwavelength operation with precise wavelength control.
• The developed EDFLs are suitable for advanced optical communication and sensing systems.