We observed the frequency upconversion of a 1313 nm Nd:YLF laser pulseinto 780 nm through the amplified spontaneous emission (ASE) in Er3+-doped and Er3+/Yb3+-doped germanosilcate single-mode optical fibers pumped by a CW mode-locked (CW+ML) laser and a Q-switched mode-locked (QS+ML) laser, respectively. The emission at780 nm corresponds to 4I9/2-4I15/2 transition, and its pumping mechanism is accomplishedby a first step resonant two-photon absorption to 4F9/2 state, fo]lowed by a fast nonradiative relaxation to 4I9/2 state. The conversion efficiency of 1313 nm light into 780 nm light pumped by the CW+ML laser is higher than pumped by the QS+ML laser with the peak laser power being several hundred times higher.