Patent ID: 7251261

Claim:
An apparatus for tuning a wavelength of a semiconductor laser comprising: a semiconductor laser, wherein a wavelength of an optical beam produced by the semiconductor laser varies as a function of a temperature of the semiconductor laser; an adjustable heat sink thermally coupled to the semiconductor laser, the heat sink having an adjustable thermal impedance, wherein a temperature of laser varies according to θΔW+ΔT, wherein θ is the thermal impedance of the heat sink and ΔW is change in power consumption and ΔT is change in temperature of the heat sink, and for substantially constant temperature of the heat sink, the temperature of the laser is adjustable by adjusting θ, the heat sink comprising a first heat sink portion thermally coupled to the semiconductor laser; and a second heat sink portion capable of being switchably thermally coupled or decoupled to the first heat sink portion; and a controller for adjusting the thermal impedance of the heat sink by adjusting a duty cycle of the thermal coupling of the second heat sink portion to the first heat sink portion to maintain the wavelength of the optical beam at a given wavelength.