碳纳米管被动锁模光纤激光器的研究

发布时间：2018-11-05 13:54

【摘要】：被动锁模光纤激光器能够输出具有极窄脉宽、高峰值功率和宽光谱的脉冲而被广泛应用于光纤通信系统、激光加工、高速医学成像和大功率激光系统等许多领域。单壁碳纳米管(SWCNT)作为可饱和吸收体具有恢复时间快、饱和光强低以及工作光谱范围宽等优点,基于SWCNT的被动锁模光纤激光器是激光技术领域的研究热点之一,研究高性能的SWCNT被动锁模光纤激光器具有重要的学术意义和应用价值。本论文对基于SWCNT的双向锁模光纤激光器、耗散孤子光纤激光器以及锁模光纤激光器中的矢量孤子特性进行了理论和实验研究,其主要研究内容如下:1.实验表征了SWCNT的可饱和吸收特性,构建了基于SWCNT的双向锁模光纤激光器并获得了稳定的双向锁模脉冲输出。双向锁模脉冲的中心波长分别为1566 nm和1566.7 nm、光谱宽度为3.7 nm和3.6 nm、脉宽为0.75 ps和0.77 ps。分析了腔内光纤双折射和腔体结构对双向锁模脉冲特性的影响,并对双向锁模光纤激光器进行了数值仿真研究。2.构建了基于SWCNT的腔内净色散为正值的被动锁模掺铒光纤激光器,获得了稳定的耗散孤子脉冲输出,输出脉冲的中心波长为1561.7 nm,光谱宽度为7.4 nm,脉宽为39.2 ps。研究了耗散孤子脉冲特性随泵浦功率以及腔内光纤双折射的变化,对输出的耗散孤子脉冲进行腔外压缩,得到的最窄压缩脉宽为0.76 ps,压缩比为51.6。3.分别对基于SWCNT的传统锁模光纤激光器和耗散孤子光纤激光器中的矢量孤子特性进行了实验研究,在不同的泵浦功率下,通过调节偏振控制器,改变腔内光纤双折射,获得了偏振锁定矢量孤子、偏振旋转锁定矢量孤子以及群速度锁定矢量孤子。4.采用“脉冲跟踪法”对基于SWCNT的耗散孤子光纤激光器进行数值仿真研究,数值模拟了激光器中耗散孤子的形成和在腔内的演化。通过改变腔内光纤双折射拍长和小信号增益系数,数值仿真得到偏振旋转锁定矢量耗散孤子以及群速度锁定矢量耗散孤子,并分析了腔内光纤双折射对矢量孤子特性的影响。
[Abstract]:Passive mode-locked fiber lasers are widely used in many fields, such as optical fiber communication systems, laser processing, high-speed medical imaging and high-power laser systems, because they can output pulses with very narrow pulse width, high peak power and wide spectrum. As a saturable absorber, single-walled carbon nanotube (SWCNT) has the advantages of fast recovery time, low saturation intensity and wide operating spectrum. Passive mode-locked fiber laser based on SWCNT is one of the hot research fields in laser technology. The study of high performance SWCNT passive mode-locked fiber laser has important academic significance and application value. In this paper, the characteristics of vector soliton in SWCNT based bidirectional mode-locked fiber laser, dissipative soliton fiber laser and mode-locked fiber laser are studied theoretically and experimentally. The main research contents are as follows: 1. The characteristic of saturable absorption of SWCNT is characterized experimentally. A bidirectional mode-locked fiber laser based on SWCNT is constructed and the stable output of bidirectional mode-locked pulse is obtained. The center wavelength of bidirectional mode-locked pulse is 1566 nm and 1566.7 nm, spectral width is 3.7 nm and 3.6 nm, pulse width is 0.75 ps and 0.77 ps., respectively. The effects of fiber birefringence and cavity structure on the characteristics of bidirectional mode-locking pulses are analyzed, and the numerical simulation of birefringence and cavity structure of bidirectional mode-locked fiber lasers is carried out. 2. A passive mode-locked erbium-doped fiber laser with positive net dispersion in cavity based on SWCNT is constructed. A stable output of dissipative soliton pulse is obtained. The center wavelength of the output pulse is 1561.7 nm, and the pulse width is 7.4 nm,. The pulse width is 39.2 ps.. The characteristics of dissipative soliton pulse with pump power and fiber birefringence in cavity are studied. The output dissipative soliton pulse is compressed out of cavity. The narrowest compression pulse width is 0.76 ps, and the compression ratio is 51.6.3. The characteristics of vector soliton in traditional mode-locked fiber laser and dissipative soliton fiber laser based on SWCNT are studied experimentally. Under different pump power, the birefringence of intracavity fiber is changed by adjusting the polarization controller. Polarization locked vector solitons, polarization rotation locked vector solitons and group velocity locked vector solitons are obtained. 4. 4. The numerical simulation of dissipative soliton fiber laser based on SWCNT is carried out by using "pulse tracking method". The formation and evolution of dissipative soliton in the cavity are numerically simulated. The polarization rotation locking vector dissipative solitons and group velocity locked vector dissipative solitons are obtained by changing the fiber birefringence beat length and the small signal gain coefficient in the cavity. The influence of fiber birefringence on the vector soliton characteristics is analyzed.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN248

【相似文献】