All-fiber tunable filter and laser based on two-mode fiber

Area of Science:

• Photonics and Optical Engineering
• Materials Science and Engineering

Background:

• Acousto-optic tunable filters (AOTFs) are crucial for wavelength selection in optical systems.
• Existing AOTF designs face challenges in ruggedness and efficiency, limiting their application in tunable lasers.

Purpose of the Study:

• To demonstrate a novel all-fiber acousto-optic tunable filter with enhanced ruggedness and efficiency.
• To analyze the mode coupling mechanism using rigorous acoustic wave modeling.
• To develop a tunable fiber laser utilizing the improved AOTF.

Main Methods:

• Fabrication of an all-fiber acousto-optic tunable filter employing a new acoustic-transducer design.
• Rigorous modeling of flexural acoustic waves to accurately analyze two-spatial-mode coupling.
• Integration of the AOTF into an all-fiber laser cavity to achieve wavelength tunability.

Main Results:

• The developed acousto-optic tunable filter exhibits improved ruggedness and efficiency compared to conventional designs.
• Accurate analysis of mode coupling was achieved through flexural acoustic wave modeling.
• A novel all-fiber tunable laser was demonstrated with a tuning range exceeding 20 nm.
• The tunable laser achieved a narrow linewidth of 0.2 nm.

Conclusions:

• The novel acoustic-transducer design significantly enhances the performance of all-fiber acousto-optic tunable filters.
• Rigorous modeling provides accurate insights into the mode coupling dynamics.
• The demonstrated tunable fiber laser showcases the practical application and effectiveness of the improved AOTF.