Author Affiliations
Abstract
Key Laboratory of Optical Fiber Sensing and Communication Networks, School of Information and Communication Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
The nonlinear physics dynamics of temporal dissipative solitons in a microcavity hinder them from attaining high power from pump lasers with a typical nonlinear energy conversion efficiency of less than 1%. Here, we experimentally demonstrate a straightforward method for improving the output power of soliton combs using a silica microrod cavity with high coupling strength, large mode volume, and high-Q factor, resulting in a low-repetition-rate dissipative soliton () with an energy conversion efficiency exceeding 20%. Furthermore, by generating an (free spectral range) soliton crystal comb in the microcavity, the energy conversion efficiency can be further increased up to 56%.
optical microcavity nonlinear optics temporal soliton Chinese Optics Letters
2023, 21(10): 101902
1 西安理工大学, 省部共建西北旱区生态水利国家重点实验室, 西安 710048
2 上海勘测设计研究院有限公司, 上海 200434
3 中国电建集团西北勘测设计研究院有限公司, 西安 710065
以纳子峡水利枢纽工程为背景, 进行了粉煤灰、纤维素纤维双掺混凝土硫酸盐干湿循环试验。基于熵权法建立了可以综合反映混凝土质量、抗压强度和抗劈拉强度的耐久性指标耐久性值(D), 分析了硫酸钠溶液质量分数和粉煤灰掺量对D值的影响, 并构建了Grey Models-Back Propagation(GM-BP)神经网络, 用以揭示混凝土D值的时变规律, 得到了不同条件下混凝土的预期寿命。结果表明: D值可以反映出硫酸钠溶液质量分数和粉煤灰掺量对混凝土耐久性的影响。180 d时, 混凝土D值损失在10%(质量分数)内与硫酸钠溶液质量分数成正比; 粉煤灰最佳掺量在10%掺量梯度下为20%; 在数据量较小时, GM-BP神经网络相比于GM模型可以更加精确地预测混凝土在盐侵-干湿循环下D值的时变规律。
混凝土 硫酸盐侵蚀 耐久性 熵权法 寿命预测 concrete sulphate attack durability entropy weight method life prediction
1 西安理工大学, 省部共建西北旱区生态水利国家重点实验室, 西安 710048
2 中国电建集团西北勘测设计研究院有限公司, 西安 710065
为了进一步认识中国西北气候环境对混凝土材料微观结构的影响, 采用纳米压痕技术对不同温湿度养护条件下混凝土的微观结构特征开展试验研究。结果表明: 从不同水化产物相的体积分数结果来看, 养护温湿度不足会使得水泥砂浆中毛细孔隙和低密度水化硅酸钙(C-S-H)凝胶含量增多。通过对不同养护条件下混凝土界面过渡区的压痕模量和硬度统计结果可知, 相比于20 ℃-95%相对湿度(RH)养护条件, 当养护条件为10 ℃-70% RH和3 ℃-50% RH时, 混凝土的界面过渡区平均厚度分别增加了5 μm和10 μm。
混凝土 养护条件 纳米压痕 微观力学 界面过渡区 concrete curing conditions nano-indentation microscopic mechanics interfacial transition zone
红外与激光工程
2022, 51(5): 20220291
红外与激光工程
2022, 51(3): 20210969
华南理工大学机械与汽车工程学院,广东 广州 510641
为了研究送粉式激光增材和铣削减材复合制造零件的表面质量及力学性能,以316L不锈钢粉末为原料,通过“增材-减材-增材-减材”交替循环的方式进行样件的制造,并对其表面粗糙度、显微硬度和力学性能进行分析测试。结果表明:送粉式激光增材和铣削减材复合制造样件的表面粗糙度随着铣削速度的增大而下降,随着每齿进给量的增加而增大;送粉式激光增材和铣削减材复合制造样件的表面粗糙度较传统工艺生产的基板试样更低,显微硬度较增材制造样件和锻造件更高,抗拉强度和屈服强度比增材制造样件分别提高了5%和60.5%,但断后伸长率却有所降低。送粉式激光增材和铣削减材复合制造技术能够制造出具有高表面质量和优良力学性能的零件,可直接应用于316L不锈钢轮胎模具等零件的制造。该技术充分融合了增材制造的高材料利用率、高自由度以及减材制造的高精度、高表面质量优势,可以获得结构复杂、形状精度和表面质量高的零件。
激光技术 激光定向能量沉积 铣削加工 复合制造 316L不锈钢 表面质量 力学性能 激光与光电子学进展
2022, 59(1): 0114009
Author Affiliations
Abstract
1 Key Laboratory of Optical Fiber Sensing and Communication Networks, School of Information and Communication Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
2 Information and Quantum Laboratory, Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, China
The dissipative Kerr soliton microcomb provides a promising laser source for wavelength-division multiplexing (WDM) communication systems thanks to its compatibility with chip integration. However, the soliton microcomb commonly suffers from a low-power level due to the intrinsically limited energy conversion efficiency from the continuous-wave pump laser to ultra-short solitary pulses. Here, we exploit laser injection locking to amplify and equalize dissipative Kerr soliton comb lines, superior gain factor larger than 30 dB, and optical-signal-to-noise-ratio (OSNR) as high as 60 dB obtained experimentally, providing a potential pathway to constitute a high-power chip-integrated WDM laser source for optical communications.
Kerr microcomb optical injection locking coherent optical communications Chinese Optics Letters
2021, 19(12): 121401
电子科技大学 光纤传感与通信教育部重点实验室,成都 611731
针对回音壁模式(WGM)光学微腔中模式高效激发的需求,基于有限元软件COMSOL对模式电场分布的计算结果,设计了一种对于WGM激发效率的仿真方法。该方法可以对微腔与锥形光纤在不同耦合条件下不同模式的谐振峰最大深度进行仿真计算,从而确定该模式得到高效激发的耦合条件。在此基础上对模式的激发效率控制和高阶方位角模式的激发进行了仿真分析,结果表明:选择尺寸匹配的锥形光纤,通过精细调整耦合距离,可以实现对所加工微棒腔的基模从欠耦合到过耦合的激发控制;通过耦合位置的调整,可以实现对其高阶方位角模式的高效激发。
回音壁模式 光学微腔 耦合效率 whispering gallery mode optical microcavity coupling efficiency
Author Affiliations
Abstract
1 School of Information and Communication Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
2 Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China
We demonstrate comprehensive investigation of the injection locking dynamics of a backscattered Brillouin laser in silica whispering-gallery-mode microcavity. Via injection locking, the Brillouin laser acquires highly correlated phase with the seed laser, enabling ultra-narrow bandwidth, high gain, and coherent optical amplification. Also, for the first time, to the best of our knowledge, the injection locked Brillouin laser is utilized to implement all-optical carrier recovery from coherent optical data signals. We show that by using the injection locked Brillouin laser as a local oscillator for self-homodyne detection, high-quality data receiving can be realized, even without traditional electrical compensations for carrier frequency and phase drifts.
optical microcavity stimulated Brillouin scattering laser injection locking self-homodyne detection Chinese Optics Letters
2021, 19(11): 111901
Author Affiliations
Abstract
Key Laboratory of Optical Fiber Sensing and Communication Networks, School of Information and Communication Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
We demonstrate a novel method to control the free spectral range (FSR) of silica micro-rod resonators precisely. This method is accomplished by iteratively applying laser annealing on the already-fabricated micro-rod resonators. Fine and repeatable increasing of resonator FSR is demonstrated, and the best resolution is smaller than 5 MHz, while the resonator quality-factor is only slightly affected by the iterative annealing procedure. Using the fabricated micro-rod resonators, single dissipative Kerr soliton microcombs are generated, and soliton repetition frequencies are tuned precisely by the iterative annealing process. The demonstrated method can be used for dual-comb spectroscopy and coherent optical communications.
microcavities nonlinear optics pulse propagation temporal solitons Chinese Optics Letters
2021, 19(7): 071903