检索结果-南通市图书馆

Coherent beam combining of two all‑PM thulium‑doped fiber chirped pulse amplifiers

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Optoelectronics 2024年第2期17卷 33-42页

作者： Bo Ren Hongxiang Chang Can Li Tao Wang Kaikai Jin Jiayi Zhang Kun Guo Rongtao Su Jinyong Leng pu zhou College of Advanced Interdisciplinary Studies National University of Defense TechnologyChangsha 410073China Nanhu Laser Laboratory National University of Defense TechnologyChangsha 410073China Hunan Provincial Key Laboratory of High Energy Laser Technology National University of Defense TechnologyChangsha 410073China

In this paper,we report a coherent beam combining(CBC)system that involves two thulium-doped all-polarization maintaining(PM)fiber chirped pulse amplifiers.Through phase-locking the two channels via a fiber stretcher by using the stochastic parallel gradient descent(SPGD)algorithm,a maximum average power of 265 W is obtained,with a CBC efficiency of 81%and a residual phase error ofλ/17.After de-chirping by a pair of diffraction gratings,the duration of the combined laser pulse is compressed to 690 fs.Taking into account the compression efficiency of 90%and the main peak energy proportion of 91%,the corresponding peak power is calculated to be 4 MW.The laser noise characteristics before and after CBC are examined,and the results indicate that the CBC would degrade the low frequency relative intensity noise(RIN),of which the integration is 1.74%in[100 Hz,2 MHz]at the maximum combined output power.In addition,the effects of the nonlinear spectrum broadening during chirped pulse amplification on the CBC efficiency are also investigated,showing that a higher extent of pulse stretching is effective in alleviating the spectrum broadening and realizing a higher output power with decent combining efficiency.

关键词： Coherent beam combining Thulium-doped fiber laser High-average power Chirped pulse amplifier

High power cladding-pumped low quantum defect Raman fiber amplifier

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Photonics Research 2024年第5期12卷 995-1003页

作者： YANG ZHANG JIANGMING Xu JUNRUI LIANG SICHENG LI JUN YE XIAOYA MA TIANFU YAO ZHIYONG PAN JINYONG LENG pu zhou College of Advanced Interdisciplinary Studies National University of Defense TechnologyChangsha 410073China Nanhu Laser Laboratory National University of Defense TechnologyChangsha 410073China Hunan Provincial Key Laboratory of High Energy Laser Technology National University of Defense TechnologyChangsha 410073China

Heat generated by the quantum defect(QD)in optically pumped lasers can result in detrimental effects such as mode instability,frequency noise,and even catastrophic damage.Previously,we demonstrated that boson-peakbased Raman fiber lasers have great potential in low QD laser generation.But their power scalability and heat load characteristics have yet to be investigated.Here,we demonstrate a boson-peak-based Raman fiber amplifier(RFA)with 815 W output power and a QD of 1.3%.The low heat generation characteristics of this low QD RFA are demonstrated.Both experimental and simulation results show that at this power level,the heat load of the low QD RFA is significantly lower than that of the conventional RFA with a QD of 4.8%.Thanks to its low heat generation characteristics,the proposed phosphosilicate-fiber-based low QD RFA provides an effective solution for the intractable thermal issue in optically pumped lasers,which is of significance in reducing the laser’s noise,improving the laser’s stability and safety,and solving the challenge of heat removing.

关键词： pumped fiber amplifier

Ultrafast laser state active controlling based on anisotropic quasi-1D material

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2024年第4期13卷 717-726页

作者： Zixin Yang Qiang Yu Jian Wu Haiqin Deng Yan Zhang Wenchao Wang Tianhao Xian Luyi Huang Junrong Zhang Shuai Yuan Jinyong Leng Li Zhan Zongfu Jiang Junyong Wang Kai Zhang pu zhou College of Advanced Interdisciplinary Studies National University of Defense TechnologyChangsha 410073China. Nanhu Laser Laboratory National University of Defense TechnologyChangsha 410073China. i-Lab&Key Laboratory of Nanodevices and Applications&Key Laboratory of Nanophotonic Materials and Devices Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123China. School of Applied and Engineering Physics Cornell UniversityIthacaNY 14853USA. State Key Laboratory of Advanced Optical Communication Systems and Networks School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China. Shanghai Key Lab of Modern Optical System University of Shanghai for Science and TechnologyShanghai 200093China

Laser state active controlling is challenging under the influence of inherent loss and other nonlinear effects in ultrafast systems.Seeking an extension of degree of freedom in optical devices based on low-dimensional materials may be a way forward.Herein,the anisotropic quasi-one-dimensional layered material Ta2PdS6 was utilized as a saturable absorber to modulate the nonlinear parameters effectively in an ultrafast system by polarization-dependent absorption.The polarization-sensitive nonlinear optical response facilitates the Ta2PdS6-based mode-lock laser to sustain two types of laser states,i.e.,conventional soliton and noise-like pulse.The laser state was switchable in the single fiber laser with a mechanism revealed by numerical simulation.Digital coding was further demonstrated in this platform by employing the laser as a codable light source.This work proposed an approach for ultrafast laser state active controlling with low-dimensional material,which offers a new avenue for constructing tunable on-fiber devices.

关键词： polarization fiber controlling

Thulium-doped all-PM fiber chirped pulse amplifier delivering 314 W average power

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

High Power Laser Science and Engineering 2023年第6期11卷 77-82页

作者： Bo Ren Can Li Tao Wang Kun Guo Jian Wu pu zhou College of Advanced Interdisciplinary Studies National University of Defense TechnologyChangshaChina Nanhu Laser Laboratory National University of Defense TechnologyChangshaChina Hunan Provincial Key Laboratory of High Energy Laser Technology National University of Defense TechnologyChangshaChina

A high-power all polarization-maintaining(PM) chirped pulse amplification(CPA) system operating in the 2.0 μm range is experimentally demonstrated.Large mode area(LMA) thulium-doped fiber(TDF) with a core/cladding diameter of25/400 μm is employed to construct the main amplifier.Through dedicated coiling and cooling of the LMA-TDF to manage the loss of the higher order mode and thermal effect,a maximum average power of 314 W with a slope efficiency of 52% and polarization extinction ratio of 20 dB is realized.The pulse duration is compressed to 283 fs with a grating pair,corresponding to a calculated peak power of 10.8 MW,considering the compression efficiency of 88% and the estimated Strehl ratio of 89%.Moreover,through characterizing the noise properties of the laser,an integrated relative intensity noise of 0.11% at 100 Hz-1 MHz is obtained at the maximum output power,whereas the laser timing jitter is degraded by the final amplifier from 318 to 410 fs at an integration frequency of 5 kHz to 1 MHz,owing to the self-phase modulation effect-induced spectrum broadening.The root-mean-square of long-term power fluctuation is tested to be0.6%,verifying the good stability of the laser operation.To the best of our knowledge,this is the highest average power of an ultrafast laser realized from an all-PM-fiber TDF-CPA system ever reported.

关键词： chirped pulse amplification high average power thulium-doped fiber laser ultrafast laser

赋能新质生产力的算法可专利性及其授权保护规则研究

在线全文

学校读者我要写书评

暂无评论

知识产权 2024年第5期 98-113页

作者：周璞首都经济贸易大学国家知识产权局专利局电学发明审查部

发展新质生产力的关键在于原创性、颠覆性的科技创新。算法是人工智能时代的新结构性力量,其迭代创新在激活新质生产力的同时也不断冲击算法专利保护规则,具体表现为算法类型演化导致规则体系不协调、当前技术性要件难以适应人工智能算... 详细信息

发展新质生产力的关键在于原创性、颠覆性的科技创新。算法是人工智能时代的新结构性力量,其迭代创新在激活新质生产力的同时也不断冲击算法专利保护规则,具体表现为算法类型演化导致规则体系不协调、当前技术性要件难以适应人工智能算法发展趋势、缺乏适应于算法业态多样化的调节工具等突出问题。在专利审查指南框架下构建赋能新质生产力的算法可专利性规则,算法专利保护规则的关键因素为“产业政策”,算法专利保护对象的核心内涵为“技术贡献”,算法专利保护规则的调节杠杆为“整体考量”,并提出算法专利保护规则的调整建议。

关键词：人工智能算法可专利性新质生产力专利审查指南

Functional Fibers and Functional Fiber‑Based Components for High‑Power Lasers

在线全文

学校读者我要写书评

暂无评论

Advanced Fiber Materials 2023年第1期5卷 59-106页

作者： Xiao Chen Tianfu Yao Liangjin Huang Yi An Hanshuo Wu Zhiyong Pan pu zhou College of Advanced Interdisciplinary Studies National University of Defense TechnologyChangsha 410073China

The success of high-power fiber lasers is fueled by maturation of active and passive fibers,combined with the availability of high-power fiber-based components.In this contribution,we first overview the enormous potential of rare-earth doped fibers in spectral coverage and recent developments of key fiber-based components employed in high-power laser systems.Subsequently,the emerging functional active and passive fibers in recent years,which exhibit tremendous advantages in balancing or mitigating parasitic nonlinearities hindering high-power transmission,are outlined from the perspectives of geo-metric and material engineering.Finally,novel functional applications of conventional fiber-based components for nonlinear suppression or spatial mode selection,and correspondingly,the high-power progress of function fiber-based components in power handling are introduced,which suggest more flexible controllability on high-power laser operations.

关键词： High-power laser Laser fiber Passive fiber-based component Functional fiber Functional fiber-based component

Revealing the dynamics of intensity fluctuation transfer in a random Raman fiber laser

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Photonics Research 2022年第3期10卷 618-627页

作者： Jun Ye Xiaoya Ma Yang Zhang Jiangming Xu Hanwei Zhang Tianfu Yao Jinyong Leng pu zhou College of Advanced Interdisciplinary Studies National University of Defense TechnologyChangsha 410073China

Temporal intensity fluctuation is one of the inherent features of fiber lasers.When utilizing the fiber lasers to pump a random Raman fiber laser(RRFL),the intensity fluctuation transfer from the pump to the random lasing could affect the output performance significantly.In this paper,we comprehensively compared the spectral,temporal,and power characteristics of an RRFL pumped by two different fiber lasers—a temporally unstable fiber oscillator and a temporally stable amplified spontaneous emission(ASE)source.Owing to less impact of the intensity fluctuation transfer,the ASE source-pumped RRFL shows∼45.3%higher maximum output power,higher spectral purity(>99.9%)and optical signal-to-noise ratio(>40dB),weaker spectral broadening,and more stable temporal behavior compared to the fiber oscillator-pumped RRFL.Furthermore,based on the temporal-spatial-coupled Raman equations and the generalized nonlinear Schrödinger equations,we numerically revealed the impact of the pump intensity fluctuations on the output characteristics of RRFLs,and found that the temporal walk-off effect played an important role in the dynamics of intensity fluctuation transfer.This work may provide a reference for designing and implementing high-performance RRFLs and promote their practicability in sensing,telecommunications,and high-power applications.

关键词： fiber pumped pump

Six kilowatt record all-fiberized and narrow-linewidth fiber amplifier with near-diffraction-limited beam quality

在线全文

学校读者我要写书评

暂无评论

High Power Laser Science and Engineering 2022年第4期10卷 1-6页

作者： Guangjian Wang Jiaxin Song Yisha Chen Shuai Ren Pengfei Ma Wei Liu Tianfu Yao pu zhou College of Advanced Interdisciplinary Studies National University of Defense TechnologyChangsha 410073China

In this work,an all-fiberized and narrow-linewidth fiber amplifier with record output power and near-diffraction-limited beam quality is presented.Up to 6.12 kW fiber laser with the conversion efficiency of approximately 78.8%is achieved through the fiber amplifier based on a conventional step-index active fiber.At the maximum output power,the 3 dB spectral linewidth is approximately 0.86 nm and the beam quality factor is M_(x)^(2)=1.43,M_(y)^(2)=1.36.We have also measured and compared the output properties of the fiber amplifier employing different pumping schemes.Notably,the practical power limit of the fiber amplifier could be estimated through the maximum output powers of the fiber amplifier employing unidirectional pumping schemes.Overall,this work could provide a good reference for the optimal design and potential exploration of high-power narrow-linewidth fiber laser systems.

关键词： fiber laser high power narrow linewidth

Cladding-pumped Raman fiber laser with 0.78%quantum defect enabled by phosphorus-doped fiber

在线全文

学校读者我要写书评

暂无评论

High Power Laser Science and Engineering 2022年第2期10卷 1-6页

作者： Xiaoya Ma Jiangming Xu Jun Ye Yang Zhang Liangjin Huang Tianfu Yao Jinyong Leng Zhiyong Pan pu zhou College of Advanced Interdisciplinary Studies National University of Defense TechnologyChangsha 410073 China

The quantum defect(QD)is an important issue that demands prompt attention in high-power fiber lasers.A large QD may aggravate the thermal load in the laser,which would impact the frequency,amplitude noise and mode stability,and threaten the security of the high-power laser system.Here,we propose and demonstrate a cladding-pumped Raman fiber laser(RFL)with QD of less than 1%.Using the Raman gain of the boson peak in a phosphorus-doped fiber to enable the cladding pump,the QD is reduced to as low as 0.78%with a 23.7 W output power.To our knowledge,this is the lowest QD ever reported in a cladding-pumped RFL.Furthermore,the output power can be scaled to 47.7 W with a QD of 1.29%.This work not only offers a preliminary platform for the realization of high-power low-QD fiber lasers,but also proves the great potential of low-QD fiber lasers in power scaling.

关键词： cladding pumping lowquantum defect phosphorus-doped fiber Ramanfiber laser