Advanced distributed feedback lasers based on composite fiber heavily doped with erbium ions. - Skvortsov, Mikhail I.; Wolf, Alexey A.; Vlasov, Alexander A.; Proskurina, Kseniya V.; Dostovalov, Alexander V.; Egorova, Olga N.; Galagan, Boris I.; Sverchkov, Sergey E.; Denker, Boris I.; Semjonov, Sergey L.; Babin, Sergey A. (Scientific Reports, 2020)