GaN-based laser diodes (LDs), which emit from UV to blue-green, are reviewed. For fabricating the UV LDs, we used the AlInGaN active layer instead of InGaN one. We demonstrated the UV LDs with a lasing wavelength 368nm under continuous-wave (cw) operation. Moreover, we fabricated the blue-green LDs whose lasing wavelength was 480 nm. It was investigated that the relationship between the threshold current density and the lasing wavelength. From our experiments, we successfully expanded the range of GaN-based LDs lasing wavelength, from UV (368 nm) to blue-green (480 nm). Regarding high power 405 nm-LDs, we could demonstrate the cw operated LD array devices with an output power of 1W by decreasing the thermal resistance of the LD chips.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.