Single-polarization large-mode-area fiber laser mode-locked with a nonlinear amplifying loop mirror

Area of Science:

• Photonics
• Laser Physics
• Materials Science

Background:

• Passively mode-locked fiber lasers are crucial for generating ultrashort pulses.
• Achieving high power and environmental stability simultaneously remains a challenge.

Purpose of the Study:

• To report the generation of high-power ultrashort pulses from a novel fiber laser design.
• To investigate the self-starting capabilities and operational regimes of the laser.
• To demonstrate environmentally stable high-power operation.

Main Methods:

• Utilized a single-polarization large-mode-area (LMA) photonic crystal fiber.
• Employed a nonlinear amplifying loop mirror (NALM) design with a non-reciprocal phase shift.
• Characterized mode-locking in soliton-like, stretched-pulse, and all-normal-dispersion regimes.

Main Results:

• Achieved stable pulses with up to 2 W average power at a 72 MHz repetition rate.
• Obtained a single-pulse energy of 28 nJ.
• Dechirped output pulses to a near transform-limited duration of 152 fs.

Conclusions:

• The proposed fiber laser oscillator offers a new method for high-power ultrafast laser sources.
• The combination of LMA fiber and NALM design ensures environmental stability.
• The laser demonstrates versatile mode-locking capabilities for various applications.