Generation of ultraviolet broadband light in a single-mode fiber

Ultraviolet broadband light spanning 337–405 nm was produced in a single-mode optical fiber primarily by stimulated Raman scattering. Pulses of 4 ns duration at 337 nm were coupled into a 50 m long ultraviolet-grade fiber featuring single-mode operation in the 320–450 nm range. Significant spectral broadening was achieved with pulses of only ∼10 W peak power. Our experiments demonstrate the potential for a source with ∼10⁴ times the spectral radiance of a quartz tungsten halogen lamp, which is currently used for many applications in this wavelength range. PACS 42.65.Ky; 42.81.Wg