title: Watt-level Er-doped and Er-Pr-codoped ZBLAN fiber amplifiers at the 2.7-2.8 microm wavelength range.
abstract: Characteristics of diode-pumped Er-doped and Er-Pr-codoped ZBLAN fiber amplifiers were investigated at the 2.7-2.8 microm wavelength range. An amplified signal of 4.6 W was obtained from the singly Er-doped amplifier for an input signal of 110 mW, corresponding to a net gain of 16.2 dB. An amplified signal of 2.65 W was obtained from the Er-Pr-codoped amplifier for an input signal of 70 mW, corresponding to a net gain of 15.8 dB. It is found that the gain bandwidth of the singly Er-doped amplifier is much narrower than that of the Er-Pr-codoped amplifier. Small gain, no gain, or even a loss for shorter-wavelength signals propagating through the singly Er-doped amplifier should attribute for the large number residual populations in the lower laser level caused by the inefficient depopulation of the energy transfer upconversion processes.
authors.affiliation: Center for High Technology Materials, University of New Mexico, Albuquerque, New Mexico 87106, USA. xszhu@email.arizona.edu
authors.forename: Xiushan
authors.initials: X
authors.lastname: Zhu
authors.forename: Ravi
authors.initials: R
authors.lastname: Jain