A tunable laser comprises a first tuner configured to select an emission wavelength of the laser; a second tuner configured to adjust a cavity mode of the laser by modifying the cavity optical path length. The second tuner is constrained by a finite tuning range. The tunable laser also comprises a controller configured to control the first and second tuners to select the emission wavelength and adjust the cavity mode in synchronization to perform phase-continuous tuning across a range larger than supported by the finite tuning range of the second tuner.