Watt-class 1.4 µm all-fiber optical frequency comb system based on Er-doped fiber laser and fiber Raman amplifier

Area of Science:

• Photonics and Laser Technology
• Nonlinear Optics
• Fiber Optics

Background:

• Generating optical frequency combs (OFCs) at 1.4 µm is difficult due to limitations of rare-earth ion gain bands.
• The 1.4 µm spectral region is crucial for various scientific and industrial applications.

Purpose of the Study:

• To develop a high-power, coherent optical frequency comb source at 1.4 µm.
• To overcome the challenges in generating OFCs outside conventional gain bands.

Main Methods:

• Nonlinear wavelength conversion of an Er-doped mode-locked fiber laser comb.
• Amplification using a lumped fiber Raman amplifier.
• Pulse compression using a grating pair compressor.

Main Results:

• A 1.4 µm OFC seed source with 38 fs pulse duration and 44 mW average power was generated.
• Amplification yielded a pulsed OFC source with 1.24 W average power, maintaining coherence.
• Compressed pulses achieved a duration of 818 fs.

Conclusions:

• Successfully demonstrated a high-power, coherent 1.4 µm pulsed optical frequency comb.
• The developed method provides a viable solution for accessing the important 1.4 µm spectral region with OFCs.