title: Three-transition cascade erbium laser at 1.7, 2.7, and 1.6 microm.
abstract: We report on an upconversion cascade laser in an erbium-doped ZBLAN fiber emitting simultaneously on the three transitions (4)S(3/2) ? (4)I(9/2) at 1.7 microm , (4)I(11/2) ? (4)I(13/2) at 2.7 microm , and (4)I(13/2) ? (4)I(15/2) at 1.6 microm . At moderate pump powers, the laser transition at 1.6 microm supports 2.7-microm lasing and permits a slope efficiency at 2.7 microm of 15% versus launched pump power. Above the threshold of upconversion lasing at 1.7 microm , the slope efficiency at 2.7 microm increases to 25.4%. Taking pump excited-state absorption into account, this value represents more than 90% of the theoretical slope efficiency. A transversely single-mode output power of 99mW is achieved at 2.7 microm.
authors.forename: M
authors.initials: M
authors.lastname: Pollnau
authors.forename: C
authors.initials: C
authors.lastname: Ghisler
authors.forename: W
authors.initials: W
authors.lastname: Lüthy
authors.forename: H P
authors.initials: HP
authors.lastname: Weber
authors.forename: J
authors.initials: J
authors.lastname: Schneider
authors.forename: U B
authors.initials: UB
authors.lastname: Unrau