Jansen, FlorianFlorianJansenStutzki, FabianFabianStutzkiOtto, Hans-JürgenHans-JürgenOttoEidam, TinoTinoEidamLiem, AndreasAndreasLiemJauregui, CesarCesarJaureguiLimpert, JensJensLimpertTünnermann, AndreasAndreasTünnermann2022-03-112022-03-112012https://publica.fraunhofer.de/handle/publica/375534Thermal waveguide changes in high power fiber lasers can have a significant effect on the waveguide properties of large mode area fibers. We demonstrate this by overcoming avoided crossings and measuring the fundamental mode shrinking.en620conference paper