Research on fiber coupling efficiency of 178mJ nanosecond pulsed lasers

Nanosecond pulsed lasers with high single-pulse energy show significant advantages in industrial fields such as material processing and laser cleaning. However, the traditional free-space or waveguide transmission methods are often limited by high energy loss, transmission distance, and difficulty in realizing flexible transmission in practical applications. This research is dedicated to exploring the realization of efficient, stable and flexible transmission of nanosecond pulsed lasers with high single-pulse energy. By combining the simulation of the effect of the decenter and tilt of the optical fiber on the coupling efficiency with the ZEMAX software, we have solved the problem of the spot defocusing in the horizontal and vertical directions caused by the thermal effect of the slab laser by precisely adjusting and optimizing the spatial positions of the lenses in the focusing system and the beam shaping system. This reduces the energy loss of the laser during the optical fiber transmission process and improves the transmission efficiency and stability. Finally, a 178mJ laser is coupled into an optical fiber with a core diameter of 800μm. The coupling efficiency is as high as 96% with a flexible transmission distance of 15m. Our research provides strong support for the development and application of laser technology.