We constructed grating- tuned external cavity semiconductor lasers using Littman and Littrow configuration, for which the wavelengths are tuned by rotation of the grating. This wavelength tunable semiconductor laser is one of the main devices of WDM optical communication. In Littman configuration, the wavelength range of about 60 nm (The C- and L-band range of 1,530~1,590 nm) was obtained by changing the incidence angle of the grating about $pm$1$^{circ}$ from the incidence angle of 70$^{circ}$. In the 40 nm tuning range, the output power variation was less than 1.25 ㏈ and the side mode suppression ratio(SMSR) was 32 ㏈. In Littrow configuration (The incidence angle and the first order diffraction angle is the same, i.e. $alpha$=$delta$), the wavelength tuning range was about 80 nm for the same conditions used in Littman configuration except the incidence angle ($alpha$=49$^{circ}$). In 60 nm tuning range, the output power variation was less than 1.5 ㏈ and SMSR was 35 ㏈.