title: Cooperative upconversion and optical gain in ion-beam sputter-deposited Er(x)Y(2-x)SiO(5) waveguides.
abstract: Single-phase, polycrystalline Er(x)Y(2-x)SiO(5) thin films were deposited by reactive ion-beam sputter deposition and rapid thermal annealing. Due to the crystalline nature, the silicate thin films provide peak Er(3+) emission cross-section of 0.9 +/- 0.02 x 10(-20) cm(2) that is higher than that in silica. Optical gain, with near 60% inversion, is achieved via optical pumping of a single-mode, ridge-type waveguide with the silicate core with an Er concentration of 1.7 x 10(20) cm(-3). Analysis of pump-power dependence of the optical gain and spontaneous emission intensity of Er(3+) indicate that the gain is limited by cooperative upconversion process, whose coefficient is determined to be (8 +/- 3) x 10(-17) cm(3)/sec.
authors.affiliation: Department of Physics, KAIST 373-1 Guseong-dong, Yuseong-Gu, Daejeon, Rep. of Korea.
authors.forename: Kiseok
authors.initials: K
authors.lastname: Suh
authors.forename: Minkyung
authors.initials: M
authors.lastname: Lee
authors.forename: Jee Soo
authors.initials: JS
authors.lastname: Chang
authors.forename: Hansuek
authors.initials: H
authors.lastname: Lee
authors.forename: Namkyoo
authors.initials: N
authors.lastname: Park
authors.forename: Gun Yong
authors.initials: GY
authors.lastname: Sung
authors.forename: Jung H
authors.initials: JH
authors.lastname: Shin