Aplicações de fibras opticas na geração de pulsos opticos ultracurtos

AUTOR(ES)
DATA DE PUBLICAÇÃO

1990

RESUMO

We have investigated picosecond nonlinear processes in optical fibers and their applications to ultrashort light pulse generation. Several experiments were performed in which we studied the role of stimulated Raman scattering, self and cross-phase modulation combined with group velocity dispersion on the generation of u1trashort pulses. In the first experiment, we investigated the stimulated Raman scattering in a P205-SiO2 based single mode fiber and found out that this fiber is much more efficient than standard fibers for cascade stimulated Raman scattering. In another experiment, we showed that 200 fs pedestal free solitons can be generated in a fiber Raman laser pumped at 1,06 m m. We als0 studied a fiber grating pulse compressor for use with a low peak power (<50 W) Nd:YAG laser pulses and found out that the grating pair third order dipersion plays an important role on the shape of the compressed pu1se. Pulses as short as 1,7 ps were obtained from the original 110 ps pulses. In another experiment, we measured the chirp of Raman and fundamental pulses for short fiber lengths (<240 m) and found out that the Raman chirp is greater than the fundamental chirp. For high Raman conversion efficiency, >30 %, the chirp of the fundamental pulse becomes nonlinear in plying that Raman generation should be avoided in fiber grating pulse compressors using short fiber lengths. We also studied, theoretically and experimentally, the cross-phase modulation between a cw wave and an intense picosec-ond pulse propagating in an optical fiber. We found that the walk-off between both waves plays an important role on the cw wave evolution. We have experimentally obtained a 20% amplitude modulation on a cw laser diode operating at 1,5 m m through cross-phase modulation

ASSUNTO(S)

fibras oticas

ACESSO AO ARTIGO

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