Abstract:An external cavity,tunable semiconductor lasers(LDs) array system was introduced.The system has Littrow configuration.The laser consisted of 24 LDs in a row,with central wavelength 810 nm and 20 W output power.The mode-locking signal selected by a grating was fed back to LD array as an inversed array image by two lenses.The system is relatively easy to adjust.0.5 nm (230 GHz) linewidth and 30 nm tunable range were obtained in the primary experiment,under the situation that all optical elements in the system were not optimized.The output power of the system is 60 % of the free running output.The experimental results indicate that a LD in the array can be mode locked with the feedback signal from other LDs,and the whole array can be mode locked while only part of the LDs in the array receive feedback signal.