Weak feedback assisted random fiber laser from 45°-tilted fiber Bragg grating

Area of Science:

• Photonics and Optical Engineering
• Laser Physics
• Fiber Optic Devices

Background:

• Random Fiber Lasers (RFLs) offer unique properties but often lack polarization control.
• Achieving high polarization extinction ratio (PER) and stable wavelengths in RFLs remains a challenge.

Purpose of the Study:

• To demonstrate a high-polarization RFL with improved PER using a hybrid gain mechanism.
• To investigate the effect of a 45°-tilted fiber Bragg grating (45°-TFBG) on RFL characteristics.
• To achieve a fixed lasing wavelength in a RFL system.

Main Methods:

• Implemented a hybrid Raman and Erbium gain system for the RFL.
• Incorporated a 45°-TFBG with extremely weak feedback (0.09% reflectivity) to tailor laser output.
• Systematically characterized the RFL performance, including PER and wavelength stability.
• Utilized numerical simulation with a power balance model to verify experimental findings.

Main Results:

• Achieved a high polarization extinction ratio (PER) of approximately 15.3 dB.
• Demonstrated the ability to fix the random lasing wavelength using the weak feedback from the 45°-TFBG.
• Experimental results were consistent with numerical simulations, validating the power balance model.

Conclusions:

• The hybrid RFL system with a 45°-TFBG effectively enhances polarization properties and stabilizes lasing wavelength.
• Weak feedback from the 45°-TFBG is crucial for boosting random lasing emission at a fixed wavelength.
• This approach offers a promising method for developing advanced RFLs for various applications.