High-Power LDA Beam Transformation using Diffractive Grating Array

摘要

Coupling high-power laser diode array (LDA) beams into a multi-mode fiber is an important way to expand the LDA applications. Transforming LDA beam is an essential step for fiber-coupled LDA. Diffractive grating arrays are used to transform a bar LDA beam with the output power of 40 watts to realize the symmetry of BPPs in fast and slow axis directions in the paper. First, the specifications of the diffractive grating are calculated according to focusing and coupling bar LDA. Second, the 8-level binary diffractive gratings are fabricated based on the binary optical elements processing platform in our lab. Third, the experiment was carried out and results are gotten. The results show that the focusing spot size is about 200um in diameter and the numerical aperture NA is 0.22, which agree with the calculated and simulated.