Low frequency Raman scattering in optical fibers

Summary form only given. The Raman gain in silica exhibits two main vibrational features, the low frequency Boson peak (/spl sim/75 cm/sup -1/) and the high frequency broad band (/spl sim/440 cm/sup -1/) (1 cm/sup -1/=30 GHz). The broad band arises from the bending motion of Si-O-Si bridges, while the Boson peak arises from what appear to be localized vibrations, although their exact origin is still, being debated. To date, studies of fiber Raman amplifiers (FRAs) have focused on the broadband peak because amplification in this region offers higher gain. We, on the other hand, have studied amplification in the Boson peak region because it may extend the available Raman bandwidth.