Tunable external cavity semiconductor laser incorporating a tunable bragg grating

A tunable laser system, comprising:

• a) a semiconductor gain medium, for providing source light, responsive to reflected light at a reflected wavelength, the gain medium including a lasing material for amplifying the reflected light, and further for providing amplified reflected light;
• b) an elongated tuner housing having a tuner housing head and having a tuner housing foot, the tuner housing head and tuner housing foot being rigidly connected;
• c) a span of waveguide having a first sampled grating in a first section of the waveguide for receiving the source light, having a second sampled grating in a second section of the waveguide for receiving the source light, the two gratings having a different sample period, both gratings for providing in turn the reflected light, both sections of the waveguide being of large-diameter so as to be able to respond to a compressive force applied along its longitudinal axis without significant buckling, the span of waveguide also having a waveguide head and a waveguide foot, the waveguide head abutting the tuner housing head and the waveguide foot disposed toward the tuner housing foot;
• and
• d) means for applying a compressive force, disposed so as to abut the waveguide foot and also to abut the tuner housing foot, responsive to a controller signal indicating the compressive force to be exerted on the span of waveguide along the direction of the axis of the span of waveguide;
• wherein the first section and second section are of different thicknesses, and the sampled gratings are inscribed in the two sections so that at any given compressive force exerted by the means for applying a compressive force, both gratings reflect at most one common wavelength.