Understanding the fundamental mechanisms of action for increasing weld depth during tem-poral power modulation in laser beam welding could allow dissimilar rotational welding without the introduction of concomitant turbulence, but with enhanced intermixing. The in-vestigations are conducted on 30 mm diameter round bars of stainless steel alloy 1.4301 and nickel base alloy 2.4856 utilizing a 16 kW disk laser beam source. Modulation frequencies are 0/50/100/200 Hz at low, medium, and high amplitudes of laser beam power. The influ-ence on the process and weld characteristics is investigated through high-speed imaging with greyscale analysis, keyhole depth measurements, metallographic sections and EDX analysis. The objectives are successfully achieved, and the underlying mechanism is main-taining the keyhole depth at a higher level for modulation frequencies of 200 Hz and a high amplitude of laser beam power, which is related to the keyhole inertia. Based on this, a nov-el welding mode with a constant keyhole depth is proposed. Furthermore, up to 20 \% in-crease in weld depth is achieved, a saturation limit for the modulation frequency is identi-fied, intermixing within the weld is enhanced and a model for predicting the weld depth based solely on measurements of the surface width is developed.