物理学报2017，Vol.66Issue(13)：100-105,6.DOI:10.7498/aps.66.134203
基于增益光纤长度优化的双波长运转掺铒光纤锁模激光器
Dual-wavelength mode-locked Er-doped fiber laser based on optimizing gain fiber length
摘要
Abstract
Recently, multi-wavelength pulsed lasers have become a research hotspot due to their versatile applications, such as precision spectroscopy, microwave/terahertz photonics, optical signal processing, and wavelength division multiplexed optical fiber communication systems. As a promising candidate, passively mode-locked fiber laser has the advantages of ultrashort pulse, ultrahigh peak power, compact structure and low-cost. In the existing multi-wavelength passively mode-locked fiber lasers, multi-wavelength mode-locked operation is achieved by adjusting the intracavity modulators to a proper state after laser has worked. It is inconvenient for practical use, so, its application scope is restricted. In this paper, a new method to achieve dual-wavelength mode-locked operation in an erbium-doped fiber laser is proposed. For an erbium-doped fiber, the peaks of both absorption and emission spectra overlap in the 1530 nm-region. So the emission light in the 1530 nm-region will be re-absorbed by the erbium-doped fiber with low pump power or long gain fiber. Utilizing the emission re-absorption effect, the gain spectrum can be modified by different lengths of gain fiber. In the experiment, an all-fiber ring cavity is adopted and a transmission-type semiconductor saturable absorber is used as a modelocker. The cavity consists of ～3.2-m-long single mode fiber and an erbium-doped fiber. Gain fibers with different lengths are used in the cavity to reveal the dependence of emission re-absorption on both gain spectrum and mode-locked output spectrum. According to the experimental results, there are two humps in the amplified spontaneous emission spectrum located in the 1530 nm-region and 1560 nm-region, respectively. With the gain fiber length increasing, gain spectrum in the 1530 nm-region is suppressed, and gain intensity in the 1560 nm-region gradually surpasses that in the 1530 nm-region. Based on the experimental results, self-starting dual-wavelength mode-locked operation is achieved with a 31-cm-long gain fiber. The two spectral peaks with close intensity are located at 1532.4 nm and 1552.3 nm, respectively. The maximum output power is 4.8 mW at a repetition rate of 58.01 MHz and a signal-to-noise ratio of 58.2 dB. This self-starting dual-wavelength mode-locked erbium-doped fiber laser is convenient for practical use and can meet the requirements for many potential applications.关键词
锁模激光器/双波长锁模运转/自启动锁模/自发辐射放大Key words
mode-locked lasers/dual-wavelength mode-locking operation/self-starting mode-locking/amplified spontaneous emission引用本文复制引用
石俊凯,纪荣祎,黎尧,刘娅,周维虎..基于增益光纤长度优化的双波长运转掺铒光纤锁模激光器[J].物理学报,2017,66(13):100-105,6.基金项目
国家自然科学基金(批准号: 61475162)、中国科学院国际合作局对外合作重点项目(批准号: 181811KYSB20160029)、中国科学院前沿科学重点研究项目(批准号: QYZDY-SSW-JSC008)和国家重大科学仪器设备专项(批准号: 2011YQ120022, 2014YQ090709)资助的课题. Project supported by the National Natural Science Foundation of China (Grant No. 61475162), the Key Project of Bureau of International Co-operation, Chinese Academy of Sciences (Grant No. 181811KYSB20160029), the Key Research Project of Bureau of Frontier Sciences and Education, Chinese Academy of Sciences (Grant No. QYZDY-SSW-JSC008), and the National Key Scientific Instruments and Equipment Development of China (Grant Nos. 2011YQ120022, 2014YQ090709). （批准号: 61475162）
