title: ASE noise independent small signal modal gain measurements and mode imaging in double clad Nd³⁺- doped fiber around 900 nm.
abstract: The spatially and spectrally resolved mode imaging method (S²) and lock-in detection technique are combined to allow for low signal gain measurements in double clad, Nd³⁺- doped fiber in the spectral region of 900 nm. The combination of these methods gives us the opportunity to measure the low signal gain, without disruption of the result by the amplified spontaneous emission (ASE). Results of the modal gain measurements are compared to numerical calculations.
authors.forename: Patrycjusz
authors.initials: P
authors.lastname: Stremplewski
authors.forename: Czeslaw
authors.initials: C
authors.lastname: Koepke