Anti-Stokes light scattering in glass fiber waveguides

An investigation was made of anti-Stokes light scattering with respect to the pump radiation under conditions of biharmonic laser pumping (λ₁ = 1064 μ, λ₂ = 1.09–1.23 μ) of few-mode and single-mode glass fiber waveguides having weak and strong birefringence. Birefringence of the waveguides under study was determined by four-photon mixing under conditions of phase matching of the interacting waves. It was shown that the emission bands observed in the 0.5–1 μ spectral range cannot be attributed to three-photon mixing. A mechanism for generation of wide-band anti-Stokes radiation in waveguides is discussed.