We conducted a study on the thermal effects in chirped volume Bragg gratings (CVBGs) used as optical compressors in high-power lasers. A simulation code was developed to predict the distortion of the pulses by the thermal effects. The types and significance of the thermal distortion were analyzed using an Yb:YAG laser with an average power of 250 W. The temperature distribution in the CVBG, the thermal lens effect, the beam propagation path changes due to the thermal lens, and the compression efficiency decrease due to the phase delay were analyzed. As a result, we predict that the peak power decreases to 63.9% due to the thermal effects under the operating conditions of 250 W. We also suggest new designs for the CVBG mount that minimize the peak power loss. We expect the peak power loss to be reduced only by 1.1% when using our new mount design for the CVBG.

We demonstrated drawbacks of CVBG compressors of picosecond pulses at average power exceeding 50W. Significant reduction of beam quality and peak intensity can be addressed to residual absorption of bulk material and induced Kerr effect.