A tuneable laser is disclosed, including a gain section with first and second comb reflectors to one side thereof. The two reflectors each provide combs with substantially uniform spacings, the spacings differing as between the combs. Each comb reflector can be tuned so as to shift the reflective peaks of the combs, thus allowing alignment of a single reflective peak at a chosen wavelength which is the same in both combs, forming a supermode. This supermode has an intensity greater than the threshold of the gain section and thus the laser produces an output at that selected wavelength.