Research on Low Numerical Aperture 808 nm Fiber-Coupled Semiconductor Laser.

Area of Science:

• Optics and Photonics
• Semiconductor Lasers
• Optical Engineering

Background:

• Efficient fiber coupling is crucial for high-power semiconductor laser systems.
• Low numerical aperture (NA) lasers present unique coupling challenges.
• Optimizing thermal management and packaging is essential for laser stability.

Purpose of the Study:

• To investigate and develop advanced fiber coupling techniques for low NA 808 nm semiconductor lasers.
• To design and implement an optical system for efficient beam shaping and fiber delivery.
• To validate the performance and applicability of the developed coupling module in high-brightness laser systems.

Main Methods:

• Fabrication of a high-power Gallium Arsenide (GaAs)-based 808 nm semiconductor laser chip.
• Design and integration of a coupling optical system using fast-axis/slow-axis collimators (FAC/SAC) and an aspheric focusing lens.
• Optimization of packaging materials and structures for enhanced thermal performance and operational stability.

Main Results:

• Achieved a coupling efficiency of 95% into a 200 μm/0.12 NA fiber.
• Demonstrated a continuous output power of 9.59 W with a slope efficiency of 1.1 W/A.
• Obtained a peak brightness of 0.72 MW/cm²·sr and a low wavelength temperature drift of ~0.2 nm/°C.

Conclusions:

• The FAC/SAC combined with a focusing lens approach is feasible and superior for low-NA fiber coupling.
• The developed coupling module provides a theoretical and practical foundation for high-brightness, high-power laser systems.
• This technology offers promising applications in solid-state laser pumping and long-distance, high-brightness transmission.