Phonon modes structure spectrum research in DCF optical fiber Stokes Raman scattering gain spectrum

摘要

DCF optical fiber Stokes Raman forward scattering and backward scattering gain spectrum have been measured by Raman laser as a pump source and high spectral resolution four grating spectrometer. There are 15 phonon modes in the Stokes forward scattering region and 18 phonon modes in the Stokes backward scattering region. In the low frequency region, there are 3 characteristic phonon modes they are 41.4cm~(-1), 68.0cm~(-1) and 96.7cm~(-1). The characteristic Raman peaks of DCF fiber is 434.7cm~(-1) and 455.4cm~(-1) that are correspond to 440cm~(-1)and 490cm~(-1) of normal single mode fiber as a function of pump power has been measured. Measured DCF Raman gain spectrum is different form that in common reference and books. The reasons are the high GeO_2concentration in DCF fiber and the developing of measuring technology.