Flexibly tunable multiwavelength Raman fiber laser based on symmetrical bending method.

Area of Science:

• Photonics and Optical Engineering
• Fiber Laser Technology

Background:

• Raman fiber lasers are crucial for various applications.
• Achieving tunable multiwavelength output often requires complex filtering systems.
• Few-mode fiber Bragg gratings offer potential for novel laser designs.

Purpose of the Study:

• To investigate a practically tunable multiwavelength Raman fiber laser.
• To demonstrate wavelength adjustability without additional multichannel filters.
• To explore control of lasing wavelengths via mechanical strain.

Main Methods:

• Utilizing few-mode fiber Bragg gratings (FBGs) in a Raman fiber laser setup.
• Investigating the effect of FBG properties on the number of lasing wavelengths.
• Applying tension and compression strain to control lasing wavelength.

Main Results:

• Achieved high-quality Raman laser output with an extinction ratio > 45 dB.
• Demonstrated adjustable number of lasing wavelengths based on FBG properties.
• Showcased dynamic control of lasing wavelength via strain-induced bending with a > 15 nm range.

Conclusions:

• A tunable multiwavelength Raman fiber laser can be realized using few-mode FBGs.
• The proposed laser design eliminates the need for external multichannel filters.
• Mechanical strain provides a practical method for dynamic wavelength control in Raman fiber lasers.