All-fiber gas Raman laser oscillator

Area of Science:

• Photonics
• Laser Physics
• Fiber Optics

Background:

• Fiber gas Raman lasers (FGRLs) are crucial for generating specific wavelengths.
• Previous FGRLs often lack compactness and require high pump powers.
• Developing efficient and compact CW FGRLs, especially for mid-infrared applications, remains a challenge.

Purpose of the Study:

• To report the first all-fiber gas Raman laser oscillator (AFGRLO).
• To demonstrate a significant reduction in the Raman threshold.
• To establish a numerical model for AFGRLO systems.

Main Methods:

• Constructed an AFGRLO by fusion splicing solid-core fibers with a hydrogen-filled hollow-core photonic crystal fiber.
• Incorporated fiber Bragg gratings at the Stokes wavelength.
• Utilized a homemade 1.54 µm fiber amplifier for pumping and observed rotational stimulated Raman scattering.

Main Results:

• Achieved a maximum output Stokes power of 1.8 W at 1693 nm.
• Demonstrated a significantly reduced Raman threshold of 0.98 W due to the resonant cavity, a ~20-fold decrease compared to single-pass structures.
• Developed and validated a numerical model for AFGRLO, showing good agreement with experimental data.

Conclusions:

• The developed AFGRLO represents a significant advancement in fiber gas Raman laser technology.
• The low threshold and compact design are highly promising for practical mid-infrared laser applications.
• The established numerical model aids in the future design and optimization of FGRLs.