title: Experimental demonstration of mode structure in ultralong Raman fiber lasers.
abstract: We present the first experimental demonstration of a resolvable mode structure with spacing c/2nL in the RF spectra of ultralong Raman fiber lasers. The longest ever demonstrated laser cavity (L=84 km), RF peaks of ~100 Hz width and spacing ~1 kHz have been observed at low intracavity powers. The width of the peaks increases linearly with growing intracavity power and is almost independent of fiber length.
authors.affiliation: Institute of Automation and Electrometry, Novosibirsk, Russia.
authors.forename: S A
authors.initials: SA
authors.lastname: Babin
authors.forename: V
authors.initials: V
authors.lastname: Karalekas
authors.forename: P
authors.initials: P
authors.lastname: Harper
authors.forename: E V
authors.initials: EV
authors.lastname: Podivilov
authors.forename: V K
authors.initials: VK
authors.lastname: Mezentsev
authors.forename: J D
authors.initials: JD
authors.lastname: Ania-Castañón
authors.forename: S K
authors.initials: SK
authors.lastname: Turitsyn