The paper analyzes the reason why 1 060 nm waveband radiation is caused in Er/Yb co-doped double-clad Optical Fiber Amplifiers(OFA)and investigates in the spectrum characteristics of this radiation by means of forward and backward pump.Comparing with the Yb doped OFA
it explains the function of Er-doped ion absorption
i.e.the output spectrum wavelength is caused to drift towards the long-wavelength side.When the pump power is increased
1 060 nm waveband radiation power will rise accordingly
which should be restrained to avoid self-excitation.