Experimental and theoretical studies of erbium-doped fiber lasers with signal up-conversion losses and pump-excited state absorption losses

This paper compares the results of experimental and theoretical studies made by the authors on high-concentration erbium-doped fiber lasers. The studies have been made for three resonator configurations. The theoretical studies and simulations take into account both signal up-conversion losses and pump-excited state absorption losses, with both losses occurring together and simultaneously at various pump powers and pump wavelengths. The results indicate that up-conversion losses are higher at longer wavelengths of 1560 nm.