The generation in an optical-fiber waveguide of a spectral continuum spanning 29000 cm-1 from the near infrared to the ultraviolet is reported. A Q-switched and mode-locked Nd:YAG laser is used to excite the fiber. An unexpected phenomenon is the generation of sum-frequency light derived from the pump frequency and the characteristic Raman Stokes frequencies of fused silica. This light is observed as visible light in cladding modes of the fiber.
© 1980 Optical Society of America
Y. Fujii, B. S. Kawasaki, K. O. Hill, and D. C. Johnson, "Sum-frequency light generation in optical fibers," Opt. Lett. 5, 48-50 (1980)