5.6  W monolithic fiber laser at 3.55  μm

Area of Science:

• Laser Physics
• Optical Engineering
• Materials Science

Background:

• Fiber lasers operating in the mid-infrared (mid-IR) spectrum are crucial for various applications, including spectroscopy and medical treatments.
• Previous mid-IR fiber laser designs have faced limitations in output power and stability due to cavity damage and inefficient power delivery.

Purpose of the Study:

• To report the development of a novel monolithic fiber laser operating at 3.55 μm.
• To achieve record-breaking output power and optical efficiency at this specific wavelength.
• To investigate the impact of fiber Bragg grating (FBG) reflectivity on laser performance and validate findings through numerical modeling.

Main Methods:

• Fabrication of a monolithic cavity using erbium-doped fluorozirconate fiber.
• Integration of two fiber Bragg gratings (FBGs) to form the laser cavity.
• Experimental characterization of output power, optical efficiency, and performance under varying FBG reflectivities.
• Development and application of numerical modeling to simulate laser cavity behavior.

Main Results:

• Demonstration of the first monolithic fiber laser operating at 3.55 μm.
• Achieved a maximum output power of 5.6 W and a total optical efficiency of 26.4%.
• The monolithic design significantly enhanced cavity stability and prevented fiber tip damage, enabling higher power output compared to previous designs (max 1.5 W).
• Numerical modeling results showed excellent agreement with experimental data across different FBG reflectivities.

Conclusions:

• The developed monolithic fiber laser represents a significant advancement in mid-IR laser technology.
• The device offers superior power, efficiency, and stability for 3.55 μm fiber laser applications.
• The findings pave the way for more robust and high-performance mid-IR fiber laser systems.