Ultra-short distributed Bragg reflector fiber laser for sensing applications

Area of Science:

• Photonics and Laser Technology
• Materials Science
• Fiber Optics

Background:

• Fiber lasers offer compact and robust laser sources.
• Distributed Bragg Reflector (DBR) lasers provide wavelength selectivity.
• Erbium (Er) and Ytterbium (Yb) co-doped fibers are common gain media for fiber lasers.

Purpose of the Study:

• To demonstrate an ultra-short distributed Bragg reflector (DBR) fiber laser.
• To investigate the performance characteristics of a miniaturized fiber laser.
• To achieve stable laser operation resistant to external perturbations.

Main Methods:

• Fabrication of an ultra-short DBR fiber laser using Er/Yb co-doped fiber.
• Characterization of lasing threshold, optical signal-to-noise ratio (OSNR), and polarization modes.
• Analysis of beat signal properties, including signal-to-noise ratio and 3-dB linewidth.
• Evaluation of longitudinal mode spacing relative to grating bandwidth.

Main Results:

• An ultra-short DBR fiber laser with a total length of 8.4 mm was successfully fabricated.
• The laser exhibited a low lasing threshold (< 1 mW) and a high optical signal-to-noise ratio (> 70 dB).
• The laser emitted two orthogonal polarization modes, generating a beat signal with approximately 70 dB SNR and a 3-dB linewidth of ~3 kHz.
• Longitudinal mode spacing was comparable to the grating bandwidth, ensuring stable operation.

Conclusions:

• The developed ultra-short DBR fiber laser demonstrates excellent performance in terms of compactness and output quality.
• The laser design inherently prevents mode hopping, making it robust against external perturbations.
• This compact and stable fiber laser has potential applications in various fields requiring precise optical signal generation.