title: Bi-doped fiber amplifier with a flat gain of 25  dB operating in the wavelength band 1320-1360  nm.
abstract: Bismuth (Bi)-doped phosphosilicate fibers have been fabricated by the modified chemical vapor deposition (MCVD)-solution doping technique under different process conditions. The influence of fabrication conditions on unsaturable loss in fibers has been investigated. Pump wavelength dependent Bi gain has been studied to obtain a flat gain over a wide bandwidth. A diode pumped all-fiber Bi-doped amplifier with a flat gain of 25±1  dB from 1320-1360 nm (40 nm) has been demonstrated for -10  dBm of input signal power with a noise figure (NF) ranging from 4-6 dB. Moreover, a small signal gain of 29 dB and a NF of 4.5 dB at 1340 nm has been achieved for an input signal power of -30  dBm.
authors.forename: N K
authors.initials: NK
authors.lastname: Thipparapu
authors.forename: A A
authors.initials: AA
authors.lastname: Umnikov
authors.forename: P
authors.initials: P
authors.lastname: Barua
authors.forename: J K
authors.initials: JK
authors.lastname: Sahu