title: Yb(3+)-ring-doped fiber for high-energy pulse amplification.
abstract: We report what is to our knowledge the first demonstration of pulse amplification in a cw-pumped fiber in which the doped gain medium has a ring shape surrounding a single-mode core. For a given pump power, ring doping reduces the gain and hence the power lost to amplified spontaneous emission. Thereby, a significantly larger amount of energy can be stored in the amplifier. Using an Yb(3+)-doped fiber pumped by 540 mW of power at 1000 nm, we measured 69 microJ of extracted pulse energy at 1047 nm, the highest value reported to date from a single-mode Yb(3+)-doped fiber. We predict that a fiber cladding pumped by a diode bar can produce pulse energies in excess of 1 mJ.
authors.forename: J
authors.initials: J
authors.lastname: Nilsson
authors.forename: R
authors.initials: R
authors.lastname: Paschotta
authors.forename: J E
authors.initials: JE
authors.lastname: Caplen
authors.forename: D C
authors.initials: DC
authors.lastname: Hanna