Phase-matched broad-band Raman amplifiers

The use of angle-tuned phase matching is shown by analysis and computer simulations to reduce limitations an the pump-laser bandwidth in Raman amplifiers of either near-collinear or crossed-beam geometries. This technique requires careful adjustment of the input beam angles and the use of prisms or gratings in the input and output beams. Simultaneous high conversion of multiple spectral lines or a broad-band spectrum can he obtained over a much wider range of temporal- and spatial-pump-intensity variations than in conventional designs. Intensity-phase print-through from multiple-line coupling can be significantly reduced, improving beam quality