Patent ID: 7386021

Claim:
A light source, said light source comprising: a semiconductor laser for emitting laser light at a first frequency; an optical fibre including a fibre Bragg grating, said fibre Bragg grating being optically coupled to said semiconductor laser for receiving said laser light; reflecting a reflected portion of said laser light towards said semiconductor laser; and allowing a transmitted portion of said laser light to pass through said fibre Bragg grating; a frequency converting optical element optically coupled to said fibre Bragg grating for receiving said transmitted portion of said laser light and converting at least a fraction of said transmitted portion of said laser light into a converted light having a second frequency different from said first frequency, said fibre Bragg grating having a temperature-dependant reflection spectrum, said frequency converting optical element including a non-linear material for converting said fraction of said transmitted portion of said laser light into said converted light having said second frequency, said second frequency being an harmonic of said first frequency, said non-linear material having a temperature-dependent conversion efficiency; an output port optically coupled to said frequency converting optical element for outputting said converted light; and a temperature controller thermally coupled to said fibre Bragg grating for modulating a temperature of said fibre Bragg grating so as to modulate said reflection spectrum, said temperature controller being further thermally coupled to said non-linear material for controlling a temperature of said non-linear material, said temperature controller including a heat pump defining a hottest section and a coldest section, said heat pump pumping heat from said coldest section to said hottest section, said fibre Bragg grating being thermally coupled to one of said hottest section and said coldest sections and said non-linear material being thermally coupled to one of said hottest and coldest sections.