A kind of optical fiber doped with CdSe/ZnS quantum dot in low concentrations was fabricated for preparing a fiber amplifier. The photoluminescence and absorption spectra transmitted through the doped fiber were measured in different doping concentrations and fiber lengths. Effects of the doping concentration and fiber length on the spectra were investigated by the experiment. Compare with the doping before, a red shift of the photoluminescence-peak wavelength was observed after the doping. The
