Patent ID: 7145923

Claim:
A tuneable laser having a gain section bounded at one end by a tunable first Bragg reflector in the form of a distributed Bragg reflector adapted to produce a comb of reflective peaks and at the other end by a tunable second distributed Bragg reflector, the second distributed Bragg reflector adapted to reflect at a plurality of wavelengths, wherein one or more wavelengths of reflective peaks of the first distributed Bragg reflector substantially coincide with one or more wavelengths at which the tunable second distributed Bragg reflector reflects prior to each of the first and second distributed Bragg reflectors being tuned, and wherein the second distributed Bragg reflector is capable of being tuned selectively through discrete segments so that one or more segments of the second distributed Bragg reflector can be tuned to a lower wavelength to reflect with a further segment of the second distributed Bragg reflector reflecting at that lower wavelength to enhance the reflectivity at that lower wavelength, the lower wavelength substantially coinciding with a peak of the first distributed Bragg reflector, thereby causing the laser to lase at that lower wavelength.