Compact single-end pumped Brillouin random fiber laser with enhanced distributed feedback

Area of Science:

• Photonics and Laser Technology
• Fiber Optics
• Nonlinear Optics

Background:

• Brillouin random fiber lasers (BRFLs) are attractive for applications requiring narrow linewidths.
• Previous BRFL designs often faced challenges with lasing instabilities and noise due to bidirectional pumping.
• Compact and stable laser sources are crucial for integrated photonic systems.

Purpose of the Study:

• To propose and demonstrate a compact Brillouin random fiber laser (BRFL) with a sub-kilohertz linewidth.
• To investigate the use of enhanced distributed Rayleigh feedback from fiber random gratings (FRGs) in a linear cavity.
• To achieve stable, single-longitudinal-mode operation with reduced lasing noise.

Main Methods:

• Utilizing a linear cavity scheme with single-end pumping.
• Employing improved fiber random gratings (FRGs) with low transmission loss for enhanced Rayleigh feedback.
• Leveraging stimulated Brillouin scattering for high-efficiency random lasing resonance of the Stokes wave.

Main Results:

• Demonstrated a compact BRFL with a narrow linewidth of approximately 0.97 kHz.
• Achieved single-longitudinal-mode operation.
• The single-end pumped scheme significantly reduced lasing instabilities and noise compared to bidirectional pumping.

Conclusions:

• The proposed single-end pumped BRFL with enhanced FRGs offers a compact and stable solution.
• This laser architecture effectively suppresses noise and instabilities inherent in bidirectional pumping schemes.
• The sub-kilohertz linewidth and compact design pave the way for practical applications in integrated photonics.