高重复频率飞秒掺镱光纤放大器

 数值分析了掺镱单模光纤放大器的最佳增益光纤长度,并在实验上对掺镱单模光纤放大器和光栅对压缩器进行了研究。以最大平均输出功率为7 mW、重复频率为25.4 MHz、脉宽为56 ps的被动锁模环形腔掺镱光纤激光器作为种子脉冲,用250 mW的976 nm单模半导体激光器分别泵浦3种不同长度的掺镱单模光纤,对种子光进行放大,并用光栅对压缩器对放大后的脉冲在不同光栅距离上进行了压缩实验研究。当掺镱单模光纤长度为1.2 m时得到了较好的放大效果,种子脉冲被放大到140 mW,相应的增益为13 dB,放大后的单脉冲能量为5.5 nJ。在光栅距离为14.1 cm时获得了最短440 fs的脉冲,压缩后的功率为43 mW,相应的峰值功率为3.8 kW。     

高重复频率飞秒掺镱光纤放大器

数值分析了掺镱单模光纤放大器的最佳增益光纤长度,并在实验上对掺镱单模光纤放大器和光栅对压缩器进行了研究。以最大平均输出功率为7 mW、重复频率为25.4 MHz、脉宽为56 ps的被动锁模环形腔掺镱光纤激光器作为种子脉冲,用250 mW的976 nm单模半导体激光器分别泵浦3种不同长度的掺镱单模光纤,对种子光进行放大,并用光栅对压缩器对放大后的脉冲在不同光栅距离上进行了压缩实验研究。当掺镱单模光纤长度为1.2 m时得到了较好的放大效果,种子脉冲被放大到140 mW,相应的增益为13 dB,放大后的单脉冲能量为5.5 nJ。在光栅距离为14.1 cm时获得了最短440 fs的脉冲,压缩后的功率为43 mW,相应的峰值功率为3.8 kW。     

High-energy femtosecond Yb-doped all-fiber monolithic chirped-pulse amplifier at repetition rate of 1 MHz

A high-energy femtosecond all ytterbium fiber amplifier based on a chirped-pulse amplification(CPA) technique at a repetition rate of 1 MHz seeded by a dispersion-management mode-locked picosecond broadband oscillator is studied.We find that the compressed pulse duration is dependent on the amplified energy,the pulse duration of 804 fs corresponds to the maximum amplified energy of 10.5 μJ,while the shortest pulse duration of 424 fs corresponds to the amplified energy of 6.75 μJ.The measured energy fluctuation is approximately 0.46% root mean square(RMS) over 2 h.The low-cost femtosecond fiber laser source with super-stability will be widely used in industrial micromachines,medical therapy,and scientific studies.     

Highly efficient 4-W Yb-doped fiber amplifier pumped by a broad-stripe laser diode

A Yb-doped double-cladding fiber amplifier is v-groove side pumped by a 100-mum -wide, broad-stripe, 975-nm laser diode. The amplifier exhibits, separately, 39% electrical-to-optical conversion efficiency, 89% internal optical-to-optical conversion efficiency, 4-W output power at 1060 nm, and a small-signal gain of 53 dB.     

Single mode MOPA structured all-fiber Yb pulse fiber amplifier at low repetition

We describe a mopa structured all-fiber 15 μm fiber amplifier cascade. A single-mode diode laser generating 1064 nm wavelength, several nanosecond pulses at 100 Hz repetition was adopted to seed a corepumping amplifier featuring a 6 μm core Yb-doped fiber. Multi-stage pulse-pumping technology was applied to eliminate ASE as much as possible and ease the heat load of the system that leads to the freedom of temperature control of the laser diode. The master oscillator-power amplifier (MOPA) generated 1064 nm, 18 ns pulse-width, 100 Hz repetition of 220 μJ single pulse energy, peak power >12 kW with single transverse output. The pulse energy of 220 μJ is the largest to date in the all-fiber MOPA amplifier with core diameter around 15 μm to our knowledge.     

High-average-power picosecond Yb-doped fiber amplifier

We report on a cladding-pumped, ytterbium-doped large-core-area fiber amplifier that is capable of generating 51.2 W of average power at a 1064-nm center wavelength, an 80-MHz repetition rate, and a 10-ps pulse duration. In an ytterbium-doped large-mode-area fiber these pulses could be amplified up to 43.2 W with diffraction-limited beam quality (M(2)~1.3) . Power scaling limitations that arise from nonlinear distortions such as self-phase modulation and stimulated Raman scattering are discussed.     

Ytterbium-doped fiber amplifier with tunable repetition rate and pulse duration

A pulsed master-oscillator power fiber amplifier (MOPFA) system based on Yb³⁺-doped large mode area (LMA) double-clad optical fiber was developed. The system generated pulses of changeable duration ranging from about 8.5 to 250.0 ns at the repetition rate of up to 500 kHz. The laser system emitted up to 22 W of average output power at the wavelength of 1064 nm.     

高功率、低量子亏损同带抽运掺镱光纤放大器

开展了基于同带抽运的高功率、低量子亏损的掺镱光纤放大器实验研究. 搭建了一台输出功率为21 W的1018 nm短波 长掺镱光纤激光器, 并利用其对双包层掺镱光纤进行同带抽运, 获得18.6 W的1080 nm波段激光输出, 光-光转换效率高达90.86%. 关键词： 光纤放大器 同带抽运 双包层光纤 转换效率     

Wide band gain flattening Yb-doped fiber amplifier

The gain flattening of Yb³⁺-doped fiber amplifier of 1053 nm band has been realized in experiment using three cascade 1 × 2 fused tapered fiber coupler. The gain flattening band is about 20 nm with less than 1 dB power fluctuation around 1053 nm, which is agree with our numerical stimulation results very well.     

掺镱光纤放大器泵浦脉宽优化

为抑制低重复频率高能脉冲光纤主振荡功率放大(MOPA)系统的放大自发辐射(ASE)效应,达到脉冲泵浦的最佳放大效果,需要对泵浦脉宽进行优化。基于求解速率方程和功率传输方程,理论研究了脉冲泵浦下掺镱光纤放大器上能级粒子数密度、光纤内存储能量、正反向放大自发辐射的瞬态响应。在给定的泵浦功率、光纤长度、纤芯面积和掺杂数密度等参数下,数值计算得到的优化泵浦脉宽为793 s。此外,实验测定了ASE的建立时间; 通过调节泵浦脉宽,测定了脉冲泵浦下掺镱光纤放大器的放大效果,实验中得到的泵浦脉宽的优化值为800 s,证明了数值模拟的正确性。     

Low-repetition rate,nanosecond,high-power pulse amplifier system based on Yb-doped rod-type fiber

We report a nanosecond-pulse amplification system based on an Yb-doped,100-μm core,rod-type photonic crystal fiber.Up to 10 W of average power with pulse energy of 1 mJ and peak power of 450 kW is obtained at the repetition rate of 10 kHz.The high-power nanosecond pulse has a good pulse shape and spectral characteristics.The usage of rod-type fibers provides a novel structure for nanosecond pulse amplification.     

Environmentally stable picosecond Yb fiber laser with low repetition rate

A SESAM-mode-locked, all-polarization-maintaining Ytterbium fiber laser producing picosecond pulses with narrow spectral bandwidth is presented. A simple linear all-fiber cavity without dispersion compensation is realized using a uniform fiber Bragg grating (FBG). Different cavity lengths are investigated and repetition rates down to 0.7 MHz are obtained. Bandwidth and pulse duration of the output pulses are mainly determined by the choice of FBG. Pulses between 30 and 200 ps are generated employing different FBGs with bandwidths between 17 and 96 pm. The experimental results are in good agreement with numerical simulations. The laser holds great potential for simple amplification setups without pulse picking.     

Dynamics of Yb-doped double clad pulsed fiber amplifier based on slow motion dynamic rate equations

A special slow motion dynamic equations are presented especially adapt to the fiber laser analyze in which a long working cycle simulation and acute state changing are both needed. It can greatly save the calculation time while keep the output result relatively accurate. Then the dynamics of nanosecond high energy low repetition rate pulsed fiber amplifier is analyzed which indicate that most energy is wasted by means of self emission between pulses and the amplified self emission (ASE) is no longer the main cause of energy depletion with proper pulsed pump. Hence, unless a relatively large input seed source is used, the light conversion efficiency of a low repetition rate pulsed laser is usually much lower than the quantum efficiency even with a pulsed pump.     

包层泵浦fs光纤放大器的实验研究

 在实验上对双包层光纤放大器进行了研究。采用新型内包层为六边形的铒镱共掺双包层光纤作为放大介质,用带尾纤的半导体激光器进行泵浦,对fs光脉冲进行放大。当用2.5 W的入纤功率泵浦50 cm长的双包层铒镱光纤时,把平均功率为10.8 mW、重复频率20.84 MHz的激光放大到176 mW,增益为12.2 dB,相应的单脉冲能量为8.1 nJ,放大后脉冲宽度为480 fs,峰值功率为16 kW。     

2.14 kW级联泵浦光纤放大器

利用大模场掺镱光纤搭建了1018 nm高功率光纤激光器,获得了476 W的最高输出功率。利用6台高亮度1018 nm光纤激光器泵浦掺镱光纤,搭建了全光纤结构的级联泵浦光纤放大器,实现了2.14 kW的最高输出功率,输出功率随泵浦功率线性增长,整体斜率效率为86.9%,M2因子为1.9。     

包层泵浦fs光纤放大器的实验研究

在实验上对双包层光纤放大器进行了研究。采用新型内包层为六边形的铒镱共掺双包层光纤作为放大介质,用带尾纤的半导体激光器进行泵浦,对fs光脉冲进行放大。当用2.5 W的入纤功率泵浦50 cm长的双包层铒镱光纤时,把平均功率为10.8 mW、重复频率20.84 MHz的激光放大到176 mW,增益为12.2 dB,相应的单脉冲能量为8.1 nJ,放大后脉冲宽度为480 fs,峰值功率为16 kW。     

2.14kW级联泵浦光纤放大器

利用大模场掺镱光纤搭建了1018nm高功率光纤激光器,获得了476 W的最高输出功率。利用6台高亮度1018nm光纤激光器泵浦掺镱光纤,搭建了全光纤结构的级联泵浦光纤放大器,实现了2.14kW的最高输出功率,输出功率随泵浦功率线性增长,整体斜率效率为86.9%,M2因子为1.9。     

1 mJ pulse bursts from a Yb-doped fiber amplifier

We demonstrate burst-mode operation of a polarization-maintaining Yb-doped fiber amplifier capable of generating 60 μJ pulses within bursts of 11 pulses with extremely uniform energy distribution facilitated by a novel feedback mechanism shaping the seed of the burst-mode amplifier. The burst energy can be scaled up to 1 mJ, comprising 25 pulses with 40 μJ average individual energy. The amplifier is synchronously pulse pumped to minimize amplified spontaneous emission between the bursts. Pulse propagation is entirely in fiber and fiber-integrated components until the grating compressor, which allows for highly robust operation. The burst repetition rate is set to 1 kHz and spacing between individual pulses is 10 ns. The 40 μJ pulses are externally compressible to a full width at half-maximum of 600 fs. However, due to the substantial pedestal of the compressed pulses, the effective pulse duration is longer, estimated to be 1.2 ps.     

Experimental study on tandem pumped fiber amplifier

We present the experimental results of a 1083 nm fiber amplifier tandem pumped by 1030 nm fiber laser. The output characteristics of the tandem pumped amplifier with cladding-pump and core-pump schemes are both investigated. The 1083 nm signal laser has not been efficiently amplified when cladding-pumped by 1030 nm laser for the weak absorption of the gain fiber. The core-pump scheme works well with the amplifier. The output properties with different gain fiber length are experimentally investigated. The maximum output power is 2.4 W with power conversion efficiency of 60%.     

Lasing characteristics of strongly pumped Yb-doped photonic crystal fiber laser

A strongly pumped Yb-doped large-mode-area photonic crystal fiber (LMA-PCF) laser is analyzed. The lasing characteristics of an improved Fabry-Perot (F-P) cavity fiber laser using LMA-PCF are studied theoretically based on a rate equation model and the exact numerical solution of the rate equations is in excellent agreement with the experimental result.