1 长春理工大学 光电工程学院 空间光电技术研究所，吉林 长春 130022
2 长春理工大学 光电工程学院 光学工程系，吉林 长春 130022
基于无波分裂脉冲产生的平坦超连续谱被报道。笔者采用非线性偏振旋转（NPR）作为锁模方法来实现耗散孤子脉冲和无波分裂脉冲的切换输出。在0.3 W的泵浦功率下，获得了耗散孤子脉冲。脉冲宽度为5.8 ps，脉冲间隔为54 ns，与11.05 m的腔长一致，信噪比为55 dB，压缩后的脉冲宽度为0.61 ps。值功率可以被提升到1.18 kW。通过适当调整腔偏振态和增加泵浦功率，耗散孤子可以演化为无波分裂脉冲。随着泵浦功率的提高，脉冲宽度从11.7 ps增加到20.2 ps，几乎增加了两倍。经过计算，时间带宽积从23.9增加到53.43。较大的啁啾可以抵抗非线性相移的影响，从而避免脉冲分裂。无波分裂脉冲的脉冲能量可以提高到3.89 nJ，是耗散孤子脉冲能量的五倍。随后，使用耗散孤子和无波分裂脉冲作为种子源去获得超连续谱。结果表明，在锥形高非线性光纤中，无波分裂脉冲产生的超连续谱范围和平坦度均优于耗散孤子脉冲。基于耗散孤子脉冲和无波分裂脉冲产生的超连续谱范围为1 400~2 000 nm，覆盖了S波段、C波段、L波段三个主要通信波段，20 dB带宽分别为310.3 nm和426.4 nm。这项工作将有助于高能量脉冲光纤激光器的发展，并提高其在超连续谱产生和光通信领域的潜在应用。
超连续谱 非线性偏振旋转 耗散孤子 无波分裂脉冲 平坦度 supercontinuum nonlinear polarization rotation dissipative soliton wave-free breaking pulse flatness 红外与激光工程
2023, 52(5): 20220745
Author Affiliations
Abstract
School of Physics Science and Information Engineering, Shandong Provincial Key Laboratory of Optical Communication Science and Technology, Liaocheng University, Liaocheng 252000, China
Wavelength-tunable dissipative solitons and amplifier similaritons have been obtained by inserting all-fiber Mach–Zehnder interferometer (MZI) filters with different free spectral ranges (FSRs) in a Yb-doped mode-locked fiber laser. The MZI filter is fabricated by splicing one segment of seven-core fiber (SCF) between two segments of single-mode fibers. The bandwidth of the filter depends on the FSR of the modulated interference curve and consequently depends on the tapered fiber diameter. Inserting MZI filters with bandwidths in a fiber laser and applying a tensile strain on the tapered SCF, both wavelength-tunable dissipative solitons and amplifier similaritons have been obtained.
mode-locked fiber laser dissipative soliton amplifier similaritons Mach–Zehnder interferometer Chinese Optics Letters
2023, 21(4): 041401
Desheng Zhao 1,2,3Bin Zhang 1,2,3,*Xiran Zhu 1,2,3Shuailin Liu 1,2,3[ ... ]Jing Hou 1,2,3,*
Author Affiliations
Abstract
1 College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha, China
2 Nanhu Laser Laboratory, National University of Defense Technology, Changsha, China
3 Hunan Provincial Key Laboratory of High Energy Laser Technology, Changsha, China
We propose a 2.1 μm high-energy dissipative soliton resonant (DSR) fiber laser system based on a mode-locked seed laser and dual-stage amplifiers. In the seed laser, the nonlinear amplifying loop mirror technique is employed to realize mode-locking. The utilization of an in-band pump scheme and long gain fiber enables effectively exciting 2.1 μm pulses. A section of ultra-high numerical aperture fiber (UHNAF) with normal dispersion and high nonlinearity and an output coupler with a large coupling ratio are used to achieve a high-energy DSR system. By optimizing the UHNAF length to 55 m, a 2103.7 nm, 88.1 nJ DSR laser with a 3-dB spectral bandwidth of 0.48 nm and a pulse width of 17.1 ns is obtained under a proper intracavity polarization state and pump power. The output power and conversion efficiency are 0.233 W and 4.57%, respectively, both an order of magnitude higher than those of previously reported holmium-doped DSR seed lasers. Thanks to the high output power and nanosecond pulse width of the seed laser, the average power of the DSR laser is linearly scaled up to 50.4 W via a dual-stage master oscillator power amplifier system. The 3-dB spectral bandwidth broadens slightly to 0.52 nm, and no distortion occurs in the amplified pulse waveform. The corresponding pulse energy reaches 19.1 μJ, which is the highest pulse energy in a holmium-doped mode-locked fiber laser system to the best of our knowledge. Such a 2.1 μm, high-energy DSR laser with relatively wide pulse width has prospective applications in mid-infrared nonlinear frequency conversion.
High Power Laser Science and Engineering
2023, 11(1): 01000e12
长春理工大学 光电工程学院，吉林 长春 130022
当超短脉冲进入高非线性光纤时，在色散和非线性效应的共同作用下，脉冲频谱中会产生一些新的频率分量，使得输出频谱比输入频谱宽得多。这种光谱被称为超连续谱。超连续谱光源具有光谱范围宽、方向性好、亮度高、空间相干性好等优点。在锁模激光器中，传统孤子、耗散孤子和类噪声脉冲可以作为种子源产生超连续谱。文中，笔者建立了一个NPR被动锁模光纤激光器来产生脉冲激光。然后，添加一段DCF以补偿腔中的色散，从而产生耗散孤子。同时，通过调节腔内PC，可以实现束缚态和耗散孤子的状态切换。输出脉冲经10 m单模光纤压缩后注入部分拉锥后的高非线性光纤以产生超连续谱。实验中，我们得到了脉宽为5.6 ps、重复频率为32 MHz、信噪比为52 dB的耗散孤子锁模脉冲，压缩后的脉冲宽度为868 fs，用作超连续谱产生。超连续谱的覆盖范围约为1200~2200 nm，其20 dB谱宽为357 nm。通过调节偏振控制器，实现耗散孤子脉冲与束缚态脉冲之间的切换，束缚态脉冲持续时间为1.4 ps，脉冲间隔为14 ps，信噪比为51 dB，产生1600~1870 nm的超连续光谱，20 dB的光谱宽度为135 nm。
超快激光器 被动锁模 超连续谱 耗散孤子 束缚态孤子 ultrafast lasers passively mode-locked supercontinuum dissipative soliton bound state soliton 红外与激光工程
2022, 51(7): 20220035
华中科技大学光学与电子信息学院武汉国家光电研究中心光谷实验室，湖北 武汉 430074
耗散孤子共振脉冲(DSR)是锁模光纤激光器的一种特殊的输出脉冲，其脉冲宽度会随着泵浦能量的增加而线性增加，同时脉冲的峰值功率被钳制，因此脉冲能量也是线性增加的。随着锁模技术和稀土元素掺杂技术的发展，耗散孤子共振脉冲光纤激光器也发展迅速。对耗散孤子共振脉冲的研究背景进行了介绍，简要说明了脉冲的产生机理以及特性，列举了不同锁模机制下DSR光纤激光器的结构，最后对国内外的研究现状以及目前的应用方向进行了综合阐述。
激光器 被动锁模技术 耗散孤子共振脉冲 光纤激光器 中国激光
2022, 49(21): 2100002
Author Affiliations
Abstract
School of Physics and Optoelectronics, Faculty of Science, Beijing University of Technology, Beijing 100124, China
The dispersive Fourier transform technique provides feasibility of exploring non-repetitive events and the buildup process in ultrafast lasers. In this paper, we report a new buildup process of dissipative solitons in a simplified mode-locked Yb-doped fiber laser, which includes more complex physics stages such as the Q-switching stage, raised and damped relaxation oscillation stages, noise-like stage, successive soliton explosions stage, and soliton breathing stage. Complete evolution dynamics of noise-like pulse and double pulse are also investigated with dispersive Fourier transform. For the noise-like pulse dynamics process, it will only experience the Q-switching and relaxation oscillation stages. In the case of dissipative soliton and noise-like pulse, the double pulse buildup behavior is manifested as the replication of individual pulses. A weak energy migration occurs between two pulses before reaching steady state. Meanwhile, real-time mutual conversion of the dissipative soliton and noise-like pulse has been experimentally observed, which appears to be instantaneous without extra physical processes. To the best of our knowledge, this is the first report on these physical phenomena observed together in a mode-locked fiber laser. The results further enrich the dynamics of mode-locked fiber lasers and provide potential conditions for obtaining intelligent mode-locked lasers with controllable output.
dispersive Fourier transform dynamics process simplified mode-locked fiber lasers dissipative soliton noise-like pulse double-pulse Chinese Optics Letters
2022, 20(8): 081402
西安邮电大学电子工程学院, 陕西 西安 710121
色散傅里叶变换技术为研究被动锁模光纤激光器中孤子各种瞬时、复杂、非重复的非线性过程提供了一种强有力的实时测量手段。利用色散傅里叶变换技术研究了基于非线性偏振旋转技术的被动锁模光纤激光器中耗散孤子分裂的整个实时动态过程。研究发现,当泵浦功率为280 mW时耗散孤子发生分裂,耗散孤子分裂前首先由噪声背景脉冲产生单孤子脉冲。与泵浦功率为180 mW时的单孤子锁模状态不同的是,分裂前的单孤子的光谱上有新的光谱成分产生。这个新的频率成分会随着孤子脉冲在谐振腔中循环的圈数不断放大和展宽,并最终演化为一个新的耗散孤子脉冲。本研究对明确被动锁模光纤激光器中耗散孤子的产生和分裂机理有着重要的意义。
光纤光学 耗散孤子 孤子分裂 锁模 光纤激光器
西安邮电大学电子工程学院，陕西 西安 710072
通过在耗散孤子锁模光纤激光器外接入马赫-曾德尔干涉仪，实现了间隔可控的耗散孤子分子超短脉冲输出。马赫-曾德尔干涉仪由两个50∶50分束器和一个可调谐时间延迟线构成。通过调节时间延迟线控制马赫-曾德尔干涉仪两臂的光程差，可以实现耗散孤子分子的间距连续可调谐。实验中实现了脉冲间隔分别为0.8、1.3、2.37、4.25、6.24、9.4、15.3 ps的耗散孤子分子，对应的光谱调制间隔分别为8.3、6.1、3.83、1.88、1.27、0.85、0.52 nm。理论分析了孤子分子的产生机理并与实验数据保持一致。本研究为实现间距可控孤子分子超短脉冲提供了一个行之有效的方法。
激光光学 耗散孤子 孤子分子 锁模光纤激光器 激光与光电子学进展
2021, 58(21): 2114013
林彦吕 1,2,3黄梓楠 1,2,3黄千千 1,2,3戴礼龙 1,2,3[ ... ]牟成博 1,2,3,*
1 上海大学通信与信息工程学院特种光纤与光接入网重点实验室, 上海 200444
2 上海大学上海先进通信与数据科学研究院, 上海 200444
3 上海大学特种光纤与先进通信国际合作联合实验室, 上海 200444
4 华中科技大学光学与电子信息学院下一代互联网接入系统国家工程实验室, 湖北 武汉 430074
采用由一对保偏45°倾斜光纤光栅构成的Lyot滤波器,设计了一台脉冲态可切换的掺镱光纤激光器。该Lyot滤波器集成了起偏器和梳状滤波器的功能,为激光器实现耗散孤子锁模提供了光谱滤波效应,从而使激光器产生了中心波长为1038.82 nm、脉冲宽度为5.2 ps的耗散孤子脉冲。随着泵浦功率的增加,非线性偏振旋转反馈机制的切换导致激光器的锁模脉冲态发生了耗散孤子脉冲与类噪声脉冲之间的多重切换。脉冲态切换过程中仅需调节泵浦功率,而不需要改变偏振控制器的状态。该脉冲态可切换激光器可以用于设计更精准可控的多功能光源。
光栅 光束传输 倾斜光纤光栅 掺镱光纤激光器 非线性偏振旋转 耗散孤子 中国激光
2021, 48(19): 1901004
