A novel wideband digitally tunable laser based on fiber Bragg grating external cavities and 1*N optical switch provides 5 ms fast tuning time with output power more than 1 dBm over whole C-band that is only limited by the laser emission bandwidth. Less than 50 pm wavelength drift over -10 to 55 oC temperature range make that the wavelength locker and monitor are not necessary in this tunable laser.