Theoretic and experimental study on large-frequency-difference side-mode injection locking of high power semiconductor lasers for laser cooling

The high power semiconductor lasers were side-mode injection locked with fr equency difference 1300 GHz with respect to its free working frequency usin g injection locking technique. The transfer of coherent characteristic betw een the master laser and slave laser was studied experimentally in detail b y using saturated absorption spectra and optical heterodyne technique. The relation of locking bandwidth versus the ratio of injection power and the m ode building process of injection locking were measured, and the experiment al locking bandwidth agreed with the side-mode locking bandwidth obtained b y multi-mode rate equation followed by injection term. The threshold inject ion light power for realizing side-mode injection locking was calculated th eortically and tested by experiment.