A wavelength tunable silicon-on-insulator (SOI) laser comprising: a laser cavity including: a semiconductor gain medium having a front end and a back end; and a phase-tunable waveguide platform coupled to the front end of the semiconductor gain medium; wherein the phase-tunable waveguide platform includes a first Distributed Bragg Reflector (DBR) and a second Distributed Bragg Reflector (DBR); at least one of the Distributed Bragg Reflectors having a comb reflectance spectrum; and wherein a mirror of the laser cavity is located at the back end of the semiconductor gain medium.