重复频率1.2 GHz皮秒脉冲全光纤掺镱激光器

研究实现了基于半导体可饱和吸收体被动锁模的高重频全光纤掺镱皮秒脉冲激光器.种子源采取环形腔结构,当抽运功率为112mW时,获得了稳定的锁模脉冲激光,其中心波长为1 064.1nm,3dB谱宽为3.6nm,脉冲宽度为4.2ps,重复频率为19.2MHz.受限于谐振腔长度,光纤激光器重复频率很难得到进一步提高.因此设计并搭建了一种基于分束器和延时光纤的全新低损耗高重频脉冲调制器,将种子激光重复频率提高到1.2GHz.该设计有效降低了脉冲在耦合过程中的能量损耗,为提高全光纤超短脉冲激光器重复频率提供了新途径.     

全光纤化2.8μm中红外被动调Q激光器数值分析

提出了一种实现全光纤中红外激光器脉冲运转的方法。利用氟化物玻璃中镝离子(Dy³⁺)的2.8μm波段的吸收截面与铒离子(Er³⁺)发射截面重合的特性,将掺镝氟化物光纤作为中红外波段的可饱和吸收体,实现2.8μm掺铒氟化物光纤激光器全光纤结构的被动调Q脉冲运转;通过在可饱和吸收体两端引入中心波长为3.1μm的光纤光栅,解决Dy³⁺上能级寿命较长所导致的高泵浦功率下Dy³⁺吸收饱和、进而导致被动调Q失效的问题。基于该结构建立了2.8μm被动调Q掺铒光纤激光器的速率方程模型,计算了可饱和吸收体的参数及其两端的谐振腔反馈条件对2.8μm激光器的脉冲运转功率和时间特性的影响。计算结果表明,通过在可饱和吸收体两端引入光纤光栅可以加快可饱和吸收体的恢复过程,使激光器能够在高泵浦功率下保持调Q脉冲运转。     

All-Solid-State Nd:YAG Laser Operating at 1064nm and 1319nm under 885nm Thermally Boosted Pumping

We report a high-effciency Nd：YAG laser operating at 1064 nm and 1319nm, respectively, thermally boosted pumped by an all-solid-state Q-switched Ti：sapphire laser at 885 nm. The maximum outputs of 825.4 m W and 459.4mW, at 1064nm and 1319nm respectively, are obtained in a 8-ram-thick 1.1 at.% Nd：YAG crystal with 2.1 W of incident pump power at 885nm, leading to a high slope efficiency with respect to the absorbed pump power of 68.5% and 42.0%. Comparative results obtained by the traditional pumping at 808nm are presented, showing that the slope efficiency and the threshold with respect to the absorbed pump power at 1064nm under the 885nm pumping are 12.2% higher and 7.3% lower than those of 808rim pumping. At 1319nm, the slope efficiency and the threshold with respect to the absorbed pump power under 885nm pumping are 9.9% higher and 3.5% lower than those of 808 nm pumping. The heat generation operating at 1064 nm and 1319 nm is reduced by 19.8% and 11.1%, respectively.     

Efficient continuous-wave eye-safe region signal output from intra-cavity singly resonant optical parametric oscillator

We report an efficient continuous-wave (CW) tunable intra-cavity singly resonant optical parametric oscillator based on the multi-period periodically poled lithium niobate and using a laser diode (LD) end-pumped CW 1064 nm Nd:YVO₄ laser as the pump source. A highly efficiency CW operation is realized through a careful cavity design for mode matching and thermal stability. The signal tuning range is 1401-1500 nm obtained by varying the domain period. The maximum output power of 2.2 W at 1500 nm is obtained with a 17.1 W 808 nm LD power and the corresponding conversion efficiency is 12.9%.     

Efficient continuous-wave eye-safe region signal output from intra-cavity singly resonant optical parametric oscillator

We report an efficient continuous-wave (CW) tunable intra-cavity singly resonant optical parametric oscillator based on the multi-period periodically poled lithium niobate and using a laser diode (LD) end-pumped CW 1064 nm Nd:YVO 4 laser as the pump source.A highly efficiency CW operation is realized through a careful cavity design for mode matching and thermal stability.The signal tuning range is 1401-1500 nm obtained by varying the domain period.The maximum output power of 2.2 W at 1500 nm is obtained with a 17.1 W 808 nm LD power and the corresponding conversion efficiency is 12.9%.     

太赫兹双芯反谐振光纤的设计及其耦合特性

设计了一种新型的太赫兹双芯反谐振光纤,利用有限元分析法对光纤的损耗特性、双芯之间的耦合特性等进行了理论分析.结果表明,单芯反谐振光纤在一定范围内改变内包层管的排列分布,其传输特性并不会受到明显的影响,据此可以改变双芯光纤的内包层管的排列分布,从而利用模式泄漏耦合机制在太赫兹波段实现双芯反谐振光纤的定向耦合.本文通过改变纤芯距离和纤芯间的间隙大小,在2.5 THz的传输频率下实现了耦合长度为0.72 m的定向耦合,这种太赫兹双芯反谐振光纤将在太赫兹光开关、调制器和耦合器等太赫兹光学器件中具有重要的应用价值.     

28.2 W波长锁定878.6 nm激光二极管共振抽运双晶体1064 nm激光器

报道了一种由波长锁定878.6 nm半导体激光器共振抽运两块不同掺杂浓度Nd:YVO4晶体串接的1064nm激光器,并与使用单块的低掺杂浓度晶体和高掺杂浓度晶体情况进行比较,实验表明利用波长锁定878.6nm半导体激光器共振抽运双晶体串接的方式,有利于降低晶体的热效应,提高光光转换效率.当抽运功率为40 W时,获得了28.2 W的1064 nm激光输出,光光转换率为70.5%,斜率效率为70.6%,相对吸收光的光光转换率76%,斜率效率为76.4%,同时该激光器在10?C—40?C的温度变化范围内具有极好的温度稳定性.     

High efficiency continuous-wave tunable signal output of an intracavity singly resonant optical parametric oscillator based on periodically poled lithium niobate

In this paper we report on a continuous-wave (CW) intracavity singly resonant optical parametric oscillator (ICSRO) based on periodically poled LiNbO₃ (PPLN) pumped by a diode-end-pumped CW Nd:YVO₄ laser. Considering the thermal lens effects and diffraction loss, an optical ballast lens and a near-concentric cavity are adopted for better operation. Through varying the grating period and the temperature, the tunable signal output from 1406~nm to 1513~nm is obtained. At a PPLN grating period of 29~μ m and a temperature of 413~K, a maximum signal output power of 820~mW at 1500~nm is achieved when the 808~nm pump power is 10.9~W, leading to an optical-to-optical conversion efficiency of 7.51%.     

基于猫眼逆反射器的大范围免调试激光器

利用具有逆反射特性的光学元件构成激光器的谐振腔,能够赋予激光器大范围免调试工作的潜力.本文讨论了谐振激光自适应无线传能/通信等新兴应用对激光器免调试工作范围的要求,设计了基于猫眼逆反射器的大范围免调试激光器,采用腔内望远镜系统和复合腔结构分别拓展激光器的工作距离范围和提升激光安全性.通过对激光谐振腔的稳定性分析和对猫眼逆反射器的像差分析,明确了球差和场曲导致的猫眼离焦分别是限制免调试激光器工作距离和视场的关键因素.实验中通过优化光学设计补偿像差,实现了端面泵浦Nd:GdVO₄激光器的大范围免调试运转.16.6W泵浦功率下,激光器接收端在1—5 m工作距离范围内移动和在±30°接收端视场范围内转动时输出功率保持在5 W以上,功率波动小于10%,无需重新准直调节.5 m工作距离下,在4.6°发射端视场内输出功率保持在其最大值的50%以上,对应接收端横向移动范围达到40 cm.本工作明确了猫眼腔免调试激光器的设计优化原则,为相关研究提供了实验结果参考.     

Single-mode antiresonant terahertz fiber based on mode coupling between core and cladding

Based on the index-induced mode coupling between the higher-order mode in core and the fundamental mode in cladding tubes, the single-mode operation can be realized in any antiresonant fibers (ARFs) when satisfying that the area ratio of cladding tube and core is about 0.46:1, and this area ratio also should be modified according to the shape and the number of cladding tubes. In the ARF with nodal core boundary, the mode in core also can couple with the mode in the wall of core boundary, which can further enhance the suppression of high-order mode. Accordingly, an ARF with conjoint semi-elliptical cladding tubes realizes a loss of higher-order mode larger than 30 dB/m; simultaneously, a loss of fundamental mode loss less than 0.4 dB/m.