Study of an Unsaturated PbSe QD-Doped Fiber Laser by Numerical Simulation and Experiment

We describe an unsaturated gain-loss model in regards to colloidal PbSe quantum dot (QD)-doped fiber laser realized previously. Based on experimental observation on the laser, the numerical simulation on the model indicates there exists a pumping threshold that depends on the QD doping concentration. There is a defined range of doping concentration, within which the laser can be generated. Available doping density depends on the fiber length, following an exponential decrease with the increased fiber length. Our model suggests a reasonable lifetime of 100 ns for the upper level of QDs in the background of UV curing adhesive, which is shorter than the lifetime reported in literatures.