Multiplexing of a mode-locked laser based on bulk Yb:KGW crystal for a flexibly tunable dual-comb solid-state laser

Dual-comb lasers are widely recognized for their extensive range of applications. In this study, we present a laser multiplexing technique for developing cavity-shared Yb:KGW solid-state dual-comb lasers. The two combs share all optical components with the exception of the end mirrors, and the light from a single pump source is split to pump two lasing modes separately. This configuration enables the simultaneous and balanced mode-locking of both lasers, although the gain material is anisotropic. At a pump power of 20 W, each laser attains an average power of 1 W with a pulse duration of 400 fs. Under free-running conditions, the standard deviation of the repetition rate difference between the two laser modes is 2.1 Hz, and the relative timing jitter is measured to be 303 fs (200 Hz, 500 Hz). The correlations of the intensity noises and phase noises between the two combs are measured. The spectra of the two combs are broadened to address the issue of non-overlapping spectra and a stable interferogram is obtained. This study presents a method for developing solid-state dual-comb lasers that allow for independent adjustment of both the pump and cavity. This capability optimizes coupling efficiency and facilitates control over the repetition rate difference while ensuring that the two lasers are configured to share as much of the optical cavity as possible.