Patent ID: 7903979

Claim:
A method comprising: externally injecting narrow-band incoherent light signal generated by a broadband incoherent light source into a light source capable of lasing through a circulator or an optical power splitter; suppressing any lasing modes outside of a bandwidth of the injected light signal by injecting the narrow-band incoherent light signal into the light source capable of lasing; locking an output wavelength of the light source capable of lasing within the bandwidth of the injected light increasing a side mode suppression ratio of the wavelength locked output by increasing a power of the injected incoherent light signal; modulating data directly onto the output wavelength of the light source capable of lasing that is locked by the injected incoherent light signal to provide a modulated signal so that when a bias current applied to the light source capable of lasing is lower than a threshold current, an output of the light source capable of lasing is a reflected incoherent light; and inserting a polarization controller between the circulator or the optical power splitter and the light source capable of lasing to increase an extinction ratio of the modulated signal.