Patent ID: 7505492

Claim:
A programmable light source comprising at least one semiconductor laser, a wavelength conversion device, and a laser controller programmed to operate the semiconductor laser wherein the semiconductor laser comprises a wavelength selective section and a gain section, an output of the semiconductor laser is coupled to an input of the wavelength conversion device, and the laser controller is programmed to: control lasing intensity of the semiconductor laser by controlling an amount of gain current I GAIN injected into the gain section of the semiconductor laser, wherein a frequency V DATA of the gain current I GAIN represents an encoded data signal; control the lasing wavelength λ 1 of the semiconductor laser by using a wavelength control signal to control the temperature T λ of the wavelength selective section, an amount of current I λ injected into the wavelength selective section, or both; modulate the lasing wavelength λ 1 of the semiconductor laser at a frequency V MOD to control the temperature T λ of the wavelength selective section, the amount of current I λ injected into the wavelength selective section, or both, wherein the frequency V MOD of the modulated control signal is selected such that the encoded data signal, which is modulated at the frequency V DATA , has relatively low data content at the frequency V MOD ; determine whether the lasing wavelength λ 1 is shorter or longer than a conversion efficiency peak of the wavelength conversion device by comparing the modulated output intensity with the modulated control signal; adjust the wavelength control signal to increase the lasing wavelength λ 1 when the comparison indicates that the lasing wavelength λ 1 is shorter than the conversion efficiency peak and decrease the lasing wavelength λ 1 when the comparison indicates that the lasing wavelength λ 1 is longer than the conversion efficiency peak; and control the lasing wavelength λ 1 of the semiconductor laser by using the adjusted wavelength control signal.