利用倾斜光纤光栅的可开关双波长光纤激光器

报导了一种在四波混频作用下利用倾斜光纤布拉格光栅进行波长选择的可开关双波长掺铒光纤激光器。通过将倾斜光纤光栅与单模光纤进行横向错位焊接,使光栅的反向LP01和LP11两个模式具有相近的有效反射率,从而可以用来进行激光器的双波长选择。接入腔内的一段高非线性光子晶体光纤引入的四波混频效应克服了模式竞争,使得双波长激光在室温下稳定振荡。腔内起偏器和偏振控制器的联合作用可产生依赖于波长的损耗,以补偿光纤光栅两反射峰峰值的大小差异。基于以上原理,通过调节腔内的偏振态,该激光器实现了室温下稳定的双波长输出,也实现了在两波长之间的转换。两波长激光均有超过45 dB的信噪比,最大的功率波动为0.8 dB     

Dual-Wavelength Erbium Fiber Laser in a Simple Ring Cavity

Abstract

By controlling the cavity loss of the modes using a variable optical attenuator, specific intensities of distributed modes can be fed back into the erbium-doped fiber to produce signals without mode competition, thus resulting in stable lasing as a means to overcome mode competition in a homogenous gain medium. Two lasing signals were obtained with peak powers of approximately ?3.475 dBm and ?4.386 dBm for wavelengths of 1,540 nm and 1,548 nm, respectively, with a side mode suppression ratio of more than 43 dB.     

基于相位采样光栅的双波长光纤激光器

提出一种基于相位采样的分布反馈式双波长光纤激光器,在不同的空间化置同时引入相位和采样周期的突变.通过理论分析,这种结构能够实现谐振腔的分离,使不同波长的光波利用不同空间位置的增益介质,克服增益介质均匀加宽引起的模式竞争,实现双波长激射.采用准分子激光器和均匀相位模板,在掺铒光纤上制作波长差为0.46 nm的舣波长光纤激光器,能够实现舣波长激射.通过实验,对激光器输出功率和光栅强度的关系进行研究,表明输出功率和光栅强度成反比.     

An Easily Switchable Dual-Wavelength Passively Mode-Locked Erbium Fiber Laser

A simple scheme of switchable dual-wavelength passively mode-locked fiber laser is demonstrated. The laser can be flexibly switched among different mode-locked states simply by tuning the cavity loss while keeping all the other cavity parameters fixed. As the cavity loss increases, the mode-locked fiber laser operates at the long-wavelength, dual-wavelength, and short-wavelength states, successively. In addition, these states can be conveniently switched without losing the mode-locked operation and the switching process is reversible as the cavity loss decreases. The mechanism is qualitatively explained by the balance between the fiber gain and the cavity loss.     

1150 nm High-Power Fiber Laser Oscillator Pumped by 976 nm Laser Diode

We present an all-fiber 1150 nm Yb-doped fiber laser oscillator pumped by a 976 nm laser diode. To suppress amplified spontaneous emission and avoid parasitic laser oscillation, we propose a long-length gain fiber and a high-reflectivity output fiber Bragg grating in the fiber laser oscillator. The 1150 nm band single-mode fiber laser with output power of 20.5 W is demonstrated at room temperature. The optical-to-optical conversion efficiency ranges up to 51.6% at the maximum output. The central wavelength of the fiber laser oscillator is 1150.35 nm, and its 3 dB spectral width is 0.72 nm. No evidence of amplified spontaneous emission, residual pump light, or parasitic laser oscillation were observed in the experiments. The high-power 1150 nm fiber laser oscillator can be used as a pump source in the development of a 3 μm Ho-doped fiber laser.     

倏逝波抽运的回音壁模式激光增益计算

倏逝波抽运条件下的回音壁模式光纤激光器增益计算,涉及抽运光束在光纤内的角度分布函数及其数值计算。基于射线光学理论,推导出了高斯分布光束及均匀分布光束经透镜耦合后在光纤内表面的角度分布函数;采用复合辛普生数值积分公式对分布函数进行了数值计算,并用分布函数计算的结果研究了抽运光沿光纤轴向以受抑全反射方式传播时产生的回音壁模式激光的增益特性。所得结果对这类光纤激光器的研究具有理论和实验参考价值。     

基于两滤波器级联和饱和吸收体的单纵模双波长光纤激光器

提出和证实了一种光纤环形激光器. 将一个带通滤波器与一个带阻滤波器级联,用一段保偏掺铒光纤作为饱和吸收体,得到了一种单纵模双波长光纤激光器. 结果表明,该激光器波长间隔为0.4 nm,边模抑制比大于49 dB.如果将两个波长进行差拍,该激光器有潜力得到49.85 GHz的微波信号.     

LD Pumped Q-Switching and Self-starting Mode-locked All Fiber Laser

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Stable Dual-Wavelength Oscillation of an Er-Doped Fiber Ring Laser at Room Temperature

We propose a simple Er-doped fiber laser configuration for achieving stable dual-wavelength oscillation at room temperature, in which a high birefringence fiber Bragg grating was used as the wavelength-selective component. Stable dual-wavelength oscillation at room temperature with a wavelength spacing of 0.23 nm and mutually orthogonal polarization stages was achieved by utilizing the polarization hole-burning effect. An amplitude variation of less than 0.7 dB over an 80 s period was obtained for both wavelengths.     

用半导体激光器作调制器的双波长可调谐锁模光纤激光器

提出一种用法布里—珀罗腔半导体激光器(F—PLD)作调制器，用线性凋啾光栅(LCFG)进行波长选择的双波长环形腔主动锁模光纤激光器。利用线性凋啾光栅在腔内的色散效应使两个波长的光脉冲通过饵光纤(EDF)时在时域上分开，从而威小了不同波长的光脉冲同时通过饵光纤时造成的竞争，因此可以在室温下获得波长间隔较小的稳定的双波长光脉冲输出。实验中成功地获得了重复频率约为2GHz，波长间隔为0．92nm的稳定双波长光脉冲，并通过调谐线性凋啾光栅中心波长的位置使激光波长可以在约3nm范围内调谐。     

双波长环形腔掺铒光纤激光器建模及模式竞争的仿真

利用Giles模型建立双波长环形腔掺铒光纤激光器模型,根据增益损耗匹配条件对1550 nm与1555 nm双波长的模式竞争进行了仿真。结果表明,在均匀增益加宽模型下,损耗谱的微小变化对激光的模式竞争过程有较大影响。当两模式各自的损耗与增益相匹配时,它们的输出功率相当; 但0.1 dB的随机损耗波动将导致两个模式输出功率的相对波动幅度分别达到9.59％和9.52％。当损耗长时间偏离匹配状态0.05 dB时,一个模式将逐渐减弱并最终湮灭,另一个模式得到增强。     

Stable Dual-Wavelength Oscillation of an Er-Doped Fiber Ring Laser at Room Temperature

We propose a simple Er-doped fiber laser configuration for achieving stable dual-wavelength oscillation at room temperature, in which a high birefringence fiber Bragg grating was used as the wavelength-selective component. Stable dual-wavelength oscillation at room temperature with a wavelength spacing of 0.23 nm and mutually orthogonal polarization stages was achieved by utilizing the polarization hole-burning effect. An amplitude variation of less than 0.7 dB over an 80 s period was obtained for both wavelengths.     

An Efficient Continuous Wave Ho:LSO Laser Double-Pass Pumped by a Linewidth-Narrowed Tm Fiber Laser

We report for the first time an efficient continuous wave Ho:LSO laser double-pass pumped by a Tm fiber laser. We achieve a maximum output power equal to 3.6 W at an absorbed pump power of 10.5 W, which corresponds to an optical-to-optical conversion efficiency of 34.3% and a slope efficiency of 59.3%. The output laser wavelength is centered at 2,105.1 nm with a linewidth of ≈2.2 nm, and the beam quality factors \( {\mathrm{M}}_x^2 \) = 1.2 and \( {\mathrm{M}}_y^2 \) = 1.1 measured by the 90/10 knife-edge method.     

能同时产生不同频率脉冲信号的双波长主动锁模光纤激光器

用两只光纤光栅（FBG）作波长选择器件，实现了一种能同时输出两个不同重复频率的光脉冲序列的双波长主动锁模环形腔光纤激光器。通过调速外加调制信号的频率，使其中一个波长工作在谐波锁模状态，另一个波长工作在有理数谐波锁模状态，实验在2GHz和2.5GHz的调制频率下都成功地获得了双波长且重复频率不同的光脉冲序列，脉冲宽度分别约为60ps和45ps。     

An Actively Mode-Locked Ho:YAG Solid-Laser Pumped by a Tm-Doped Fiber Laser

An actively mode-locked Ho:YAG laser pumped by a diode-pumped Tm-doped fiber laser is reported.For the cw operation,we obtain the maximum output power of 3.43 W with a central wavelength 2022.2 nm at the maximum incident pump power of 11.4 W,corresponding to a slope efficiency of 34.5%.The beam quality factor M2 is 1.16,and the output beam is close to fundamental TEM_(00) In the case of the CWML operation,a stable pulse train is generated with an average output power up to 3.41 W with a slope efficiency of 34.3%at the incident pump power of 11.4 W and a pulse duration of 294 ps at a repetition rate of 81.92 MHz.In addition,the maximum single pulse energy is 41.6 n J.     

双波长自注入式光纤光栅外腔脉冲半导体激光器

提出了一种两个光纤光栅作法布里－珀罗半导体激光器的外反馈元件，在外加正弦信号的驱动下工作在增益开关状态的双波长自注入式脉冲半导体激光器。对两个波长对应的谐振腔的腔长相同与不同的两种情况进行了实验研究，并成功地获得了波长为1555．97nm和1557．9nm，脉冲宽度约为45ps和70ps，重复频率约为2GHz的双波长光脉冲信号。     

脉冲泵浦掺镱双包层光纤激光器的动力学研究

对脉冲泵浦的掺镱双包层光纤激光器进行了实验研究.采用重复频率1-10 kHz、脉宽100 μs的976 nmLDs泵浦,实现了脉宽小于10 ns的稳定激光脉冲输出.并对该激光器的动力学过程进行了分析,首次提出了在脉冲泵浦光纤激光器中产生ns脉冲是瑞利散射和受激布里渊散射共同作用的结果.     

Evaluation of the Performance of an HO:yap Laser Resonantly Pumped by a Thulium Fiber Laser

We investigate the continuous-wave performance of an Ho:YAP laser resonantly pumped by a Tm fiber laser at different output transmittance of 20 %, 30 %, and 50 %. We use a 40 mm long a-cut crystal with 0.5 at.% Ho ion. Our experimental results show that the best power performance is obtained at an output transmittance of 30 %. At an absorbed pump power of 12.1 W, we obtain a maximum output power of 6.1 W at 2118.1 nm with a slope efficiency of 63.4 %. The laser operates at the TEM₀₀ mode with a beam quality factor M ₂ ~ 1.5 measured using a 90/10 knife-edge method.     

Tunable Dual-Wavelength Fiber Laser in a Novel High Entropy van der Waals Material

Fiber lasers with different net dispersion cavity values can produce some types of solitons, and rich nonlinear dynamics phenomena can be achieved by selecting different saturable absorbers. A new layered high-entropy van der Waals material(HEX)(Mn,Fe,Co,Ni)PS₃ was selected as a saturable absorber to achieve a high-power laser output of 34 m W. In addition, the wavelength can be dynamically tuned from 1560 nm to 1531 nm with significant dual-wavelength phenomena at 460 fs pulse durati...     

Dual-Wavelength Passively Q-Switched Ytterbium-Doped Fiber Laser Based on Aluminum Oxide Nanoparticle Saturable Absorbers

We report on generation of a dual-wavelength, all-fiber, passively Q-switched ytterbium-doped fiber laser using aluminum oxide nanoparticle(Al_2 O_3-NP) thin flm. A thin film of Al_2 O_3 was prepared by embedding Al_2 O_3-NPs into a polyvinyl alcohol(PVA) as a host polymer, and then inserted between two fiber ferrules to act as a saturable absorber(SA).By incorporating the Al_2 O_3-PVA SA into the laser cavity,a stable dual-wavelength pulse output centered at 1050 and 1060.7 nm is observed at threshold pump power of 80 mW. As the pump power is gradually increased from 80 to 300 mW, the repetition rate of the generated pulse increases from 16.23 to 59 kHz, while the pulse width decreases from 19 to 6μs. To the best of our knowledge, this is the first demonstration for this type of SA operating in the 1 μm region.