Experimental Realization of a PbSe-Quantum-Dot Doped Fiber Laser

We experimentally demonstrate laser generation for the first time by using PbSe quantum dots (QDs) as the lasing gain medium in an all-fiber ring resonator. The resonator is configured with the PbSe QD-doped fiber (QDF), pumping laser diode, wavelength division multiplexer, fiber Bragg grating, isolator, and coupler. An obvious excitation threshold up to several tens of milliwatts is observed in experiment upon 980-nm pump. The laser generation is only observed when this threshold is reached or exceeded, and then the output power increases linearly with the pump level. The observed laser output is multimode for the QDF with large mode filed; nevertheless, single mode can be selected out by bending fiber. Upon a 68-mW pump, the laser output with single mode comes to 6.36 mW, pumping efficiency of 9.3%. The lasing peak is 6.1 dBm at the central wavelength with spectral-line width < 0.1 nm.