All-fiber GHz few-cycle pulse generation at 2 µm

Area of Science:

• Optics and Photonics
• Fiber Lasers
• Ultrafast Lasers

Background:

• Mode-locked fiber lasers are crucial for generating ultrashort optical pulses.
• Few-cycle pulses are essential for nonlinear optical phenomena and high-resolution spectroscopy.
• Existing systems often face limitations in power, stability, or complexity.

Purpose of the Study:

• To demonstrate a novel all-fiber GHz mode-locked laser system operating at 2 µm.
• To achieve watt-level few-cycle pulse output with high stability.
• To provide a robust laser source for advanced scientific applications.

Main Methods:

• Utilized a dispersion-managed mode-locked oscillator.
• Employed a multi-stage fiber amplifier for power scaling.
• Incorporated a nonlinear pulse compressor to shorten pulse duration.
• Integrated the components into a compact all-fiber system.

Main Results:

• Achieved few-cycle pulse duration of 33 fs (approx. 5 optical cycles).
• Delivered watt-level average power of 4.17 W at a 1.041 GHz repetition rate.
• Demonstrated excellent power stability with integrated relative intensity noise (RIN) of 0.052% (10 Hz–1 MHz).

Conclusions:

• The developed 2-µm all-fiber laser system offers unprecedented performance for few-cycle pulse generation.
• This laser source is highly promising for frontier applications such as coherent supercontinuum generation, nonlinear frequency conversion, and laser-material interaction.
• The all-fiber architecture ensures robustness and potential for further development.