Patent ID: 7298546

Claim:
An ultraviolet light source comprising: a laser light source, which generates light in an infrared-to-visible range, an optical amplifier, which comprises a plurality of stages of fiber optical amplifiers for amplifying the light generated by the laser light source sequentially; and a wavelength-converting optical system, which comprises at least one wavelength conversion crystal and converts the light amplified by the optical amplifier into ultraviolet light as an output, wherein the plurality of stages of fiber optical amplifiers includes a final stage of fiber optical amplifier having an excitation light source made by a single mode fiber laser, and the light input into the final stage of fiber optical amplifier which is amplified by the upstream stages of said fiber optical amplifier is mixed coaxially with the excitation light from the single mode fiber laser by a Wavelength Division Multiplexer (WDM) provided at an input port of the final stage of fiber optical amplifier.