Ultrashort optical pulse sources have important applications in optical analog-to-digital conversion, optical fiber communication, optical THz communication, microwave photonics and other systems. Mode-locking technology is a common method for generating ultrashort pulses. Various types of mode-locked lasers, such as solid-state mode-locked lasers, fiber mode-locked lasers, and semiconductor mode-locked lasers, can be used to generate short pulse outputs with different repetition frequencies. In optical analog-to-digital conversion systems and optical fiber communication systems, it is usually desired that the sampling light source or multi-wavelength light source has the characteristics of high repetition frequency, short pulse, small size, low cost, and mass production. Semiconductor mode-locked lasers are ideal light sources that meet the above requirements. A 1.5 μm high repetition frequency ultrashort optical pulse source based on a semiconductor mode-locked laser is developed for applications such as high-speed optical sampling, optical frequency comb and optical communication system. By adopting the AlGaInAs/InP material system, a two-section monolithic integrated mode-locking structure with a dilution waveguide layer is developed to decrease the optical confinement factor, increase the saturation energy, reduce the cavity loss, so as to reduce the influence of the gain dispersion and increase the peak pulse power. Finally, a subpicosecond optical pulse with a repetition rate of 24.3 GHz and pulse width of 680 fs is achieved in 1.5 μm band, with a spectral width of 7.2 nm and a peak pulse energy of 525 mW.