Abstract

The pump excited-state absorption (ESA) in the 800-nm excitation range is a well-known phenomenon¹ occurring in Er-doped silica fibers used as amplifiers or lasers.² Pumping the fiber in the 800-nm range leads to excite the ⁴I_9/2 level and quasi instantaneously populate the ⁴I_13/2level via non radiative transitions. Others pump photons from this metastable level populate higher energy levels, such that an important part of the absorbed pump power is inefficient, lowering the gain of the 1.55-μm transition. We present a spectroscopic study of the resulting green fluorescence, based on its response to the excitation wavelength, and its thermal behavior.

© 1994 IEEE