Patent ID: 7447246

Claim:
A Q-modulated semiconductor laser comprising: a first resonant optical cavity containing a first partially reflecting element at the front end of the laser from which the output power emits, a second partially reflecting element, and a first optical waveguide segment placed between said first and second partially reflecting elements, said first optical waveguide segment being sandwiched between a pair of electrodes for injecting current to provide optical gain, a second substantially anti-resonant optical cavity acting as a high-reflection mirror at the rear end of the laser, said second substantially anti-resonant optical cavity having an optical length such that its round-trip phase is substantially equal to an odd-integer multiple of π and comprising (1) a second optical waveguide segment having a variable optical loss, (2) the second partially reflecting element coupling the first end of the second optical waveguide segment to the first optical waveguide segment, and (3) a third partially reflecting element at the second end of the second optical waveguide segment, said second optical waveguide segment being sandwiched between a pair of electrodes for providing an electrical signal to change the optical loss of said second optical waveguide segment, and consequently to change the Q-factor of the first resonant optical cavity, and hence to modulate the threshold and the output power of the laser.