All-fiber Q-switched single-frequency Tm-doped laser near 2 mum

Area of Science:

• Photonics and Laser Technology
• Fiber Optics
• Quantum Electronics

Background:

• Single-frequency lasers are crucial for applications requiring high spectral purity.
• Fiber lasers offer advantages in robustness, efficiency, and beam quality.
• Operation in the eye-safe region (e.g., near 2 micrometers) is desirable for certain applications.

Purpose of the Study:

• To develop and demonstrate an all-fiber Q-switched single-frequency laser oscillator.
• To achieve operation in the eye-safe spectral region around 1950 nm.
• To characterize the performance of the developed laser system.

Main Methods:

• Utilized a Thulium (Tm)-doped fiber laser.
• Implemented stress-induced polarization modulation for Q-switching.
• Employed a distributed Bragg reflector (DBR) fiber laser configuration.

Main Results:

• Achieved Q-switched single-frequency laser operation at 1950 nm.
• Demonstrated a tunable pulse repetition rate from tens of Hz to hundreds of kHz.
• Obtained an average output power of several milliwatts.
• Characterized pulse duration and spectral linewidth.

Conclusions:

• This work represents the first demonstration of a Q-switched single-frequency fiber laser operating near 2 micrometers.
• The developed laser is suitable for applications requiring eye-safe, single-frequency pulsed operation.
• The stress-induced polarization modulation technique is effective for Q-switching in Tm-doped fiber lasers.