Mode-locked Er-doped fiber laser based on PbS/CdS core/shell quantum dots as saturable absorber

• Published in: Optics express 2018-04, Vol.26 (7), p.9017-9026
• Main Authors: Ming, Na, Tao, Shina, Yang, Wenqing, Chen, Qingyun, Sun, Ruyi, Wang, Chang, Wang, Shuyun, Man, Baoyuan, Zhang, Huanian
• Format: Article
• Language: English
• ISSN: 1094-4087
• DOI: 10.1364/OE.26.009017

Previously, PbS/CdS core/shell quantum dots with excellent optical properties have been widely used as light-harvesting materials in solar cell and biomarkers in bio-medicine. However, the nonlinear absorption characteristics of PbS/CdS core/shell quantum dots have been rarely investigated. In this work, PbS/CdS core/shell quantum dots were successfully employed as nonlinear saturable absorber (SA) for demonstrating a mode-locked Er-doped fiber laser. Based on a film-type SA, which was prepared by incorporating the quantum dots with the polyvinyl alcohol (PVA), mode-locked Er-doped operation with a pulse width of 54 ps and a maximum average output power of 2.71 mW at the repetition rate of 3.302 MHz was obtained. Our long-time stable results indicate that the CdS shell can effectively protect the PbS core from the effect of photo-oxidation and PbS/CdS core/shell quantum dots were efficient SA candidates for demonstrating pulse fiber lasers due to its tunable absorption peak and excellent saturable absorption properties.