Experimental realization of a PbSe quantum dot doped fiber amplifier with ultra-bandwidth characteristic

Using PbSe quantum dots (QDs) as the gain medium doped in UV-gel, we experimentally demonstrate a PbSe QDs doped fiber amplifier (QDFA) with ultra-bandwidth characteristics and low noise level. The QDFA consists of QD doped fiber, wavelength division multiplexer, 980 nm pumping LD, and isolator. For the doped fiber in 50 µm diameter, the observed pumping threshold is 62 mW, 1 dB flat bandwidth is 90 nm, the maximum signal gain is 12 dB, and noise figure is 3.68-3.77 dB in the wavelength region of 1250-1370 nm. The realized QDFA possesses the wider bandwidth due to the broadband-emission spectrum depending on the size distribution of QDs and lower noise compared with the popular erbium doped fiber amplifiers (EDFAs). The QDFA presented in this paper provides an alternative solution to the growing demand of the broadband fiber amplifiers in dense wavelength division multiplexing systems.