The stimulated Brillouin scattering （SBS） threshold enhancement factor in a pure white noise linewidth broad- ening Yb-doped fiber amplifier （YDFA） with a short large mode area fiber is theoretically and experimen...The stimulated Brillouin scattering （SBS） threshold enhancement factor in a pure white noise linewidth broad- ening Yb-doped fiber amplifier （YDFA） with a short large mode area fiber is theoretically and experimentally studied. We demonstrate a 1064.08nm, 11.6 GHz finewidth, 1.5 k W output power YDFA with an SBS threshold enhancement of -57 （26 W SBS threshold with single frequency seed）. The output beam is near-diffraction lim- ited with a beam quality factor elM2 = 1.15 and a slope efficiency of up to 87%. No SBS or stimulated Raman scattering effects are observed in the whole power range. Further power sealing is limited by the available pump power in our system.展开更多
We report the passive phase locking of four high power Yb-doped fiber amplifiers with ring cavity.The interference patterns at different output power are observed and the Strehl ratios are measured.The maximum coheren...We report the passive phase locking of four high power Yb-doped fiber amplifiers with ring cavity.The interference patterns at different output power are observed and the Strehl ratios are measured.The maximum coherent output power of the fiber array is up to 1062 W by multi-stage amplification.The stable beam profiles of various phase relationships are observed by controlling the position of the feedback fiber,in good agreement with the calculated results.By using master oscillator power-amplifier(MOPA)architecture and broadband operation of passively phased systems,higher power scaling with high beam quality appears to be feasible.展开更多
We investigate the lasing characteristics of a laser-diode-array side-pumped electro-optic Q-switched Nd： Y3Al5O12 ceramic laser operating at 1000 Hz pulse repetition rate. Using a YAG polycrystalline rod with Nd^3＋...We investigate the lasing characteristics of a laser-diode-array side-pumped electro-optic Q-switched Nd： Y3Al5O12 ceramic laser operating at 1000 Hz pulse repetition rate. Using a YAG polycrystalline rod with Nd^3＋ concentration of 1 at. % as the gain medium, pumping with 808 nm laser-diode-arrays, the Q-switched laser output at 1064 nm wavelength with 23mJ pulse energy and less than 12ns FWHM pulse width are obtained at a pumping power of about 400 W, the slope efficiency is around 15%, the output beam divergence angle is about 1.2mrad.展开更多
In order to increase the power fraction of the central lobe in the coherent beam combination of lasers in an array,the effects of the distance factor of near-field distribution on far-field interference patterns are c...In order to increase the power fraction of the central lobe in the coherent beam combination of lasers in an array,the effects of the distance factor of near-field distribution on far-field interference patterns are calculated and demonstrated experimentally.An improved beam array of interwoven distribution is demonstrated to enable the power in the central lobe to reach 41%.An optimized mirror array is carefully designed to obtain a high duty ratio,which is up to 53.3% at a high power level.By using these optimized methods and designs,the passive phase locking of eight Yb-doped fiber amplifiers with ring cavities are obtained,and a pleasing interference pattern with 87% visibility is observed.The maximum coherent output power of the system is up to 1066 W.展开更多
高亮度、窄线宽光纤激光光源在相干通信、激光雷达、相干/光谱合成、高能粒子加速器、聚变点火和激光冷却等领域具有重大的研究价值和广阔的应用前景。然而,光纤中的非线性效应以及大模场光纤的模式不稳定（MI）效应是保证光谱纯度和光...高亮度、窄线宽光纤激光光源在相干通信、激光雷达、相干/光谱合成、高能粒子加速器、聚变点火和激光冷却等领域具有重大的研究价值和广阔的应用前景。然而,光纤中的非线性效应以及大模场光纤的模式不稳定（MI）效应是保证光谱纯度和光束质量的同时进行输出功率定标放大的主要限制因素,因此,采用创新技术手段突破这两个限制因素是现阶段窄线宽光纤激光的研究焦点,引起国内外主流研究机构的重点关注。最近,2015年,德国Jena大学实现了45 GHz线宽,输出功率2.3 k W的近衍射极限光纤激光,展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos U1330134,61308024 and 11174305the National High-Technology Research and Development Program of China under Grant No 2014AA041901the Shanghai Natural Science Foundation under Grant No 11ZR1441400
文摘The stimulated Brillouin scattering （SBS） threshold enhancement factor in a pure white noise linewidth broad- ening Yb-doped fiber amplifier （YDFA） with a short large mode area fiber is theoretically and experimentally studied. We demonstrate a 1064.08nm, 11.6 GHz finewidth, 1.5 k W output power YDFA with an SBS threshold enhancement of -57 （26 W SBS threshold with single frequency seed）. The output beam is near-diffraction lim- ited with a beam quality factor elM2 = 1.15 and a slope efficiency of up to 87%. No SBS or stimulated Raman scattering effects are observed in the whole power range. Further power sealing is limited by the available pump power in our system.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60908011 and 60907045the National High Technology Research and Development Program of China under Grant No 2008AA03Z405the National Science and Technology Major Project of China under Grant No 2010ZX04013 and the Shanghai“Phosphor”Science Foundation under Grant No 09QB1401700.
文摘We report the passive phase locking of four high power Yb-doped fiber amplifiers with ring cavity.The interference patterns at different output power are observed and the Strehl ratios are measured.The maximum coherent output power of the fiber array is up to 1062 W by multi-stage amplification.The stable beam profiles of various phase relationships are observed by controlling the position of the feedback fiber,in good agreement with the calculated results.By using master oscillator power-amplifier(MOPA)architecture and broadband operation of passively phased systems,higher power scaling with high beam quality appears to be feasible.
文摘We investigate the lasing characteristics of a laser-diode-array side-pumped electro-optic Q-switched Nd： Y3Al5O12 ceramic laser operating at 1000 Hz pulse repetition rate. Using a YAG polycrystalline rod with Nd^3＋ concentration of 1 at. % as the gain medium, pumping with 808 nm laser-diode-arrays, the Q-switched laser output at 1064 nm wavelength with 23mJ pulse energy and less than 12ns FWHM pulse width are obtained at a pumping power of about 400 W, the slope efficiency is around 15%, the output beam divergence angle is about 1.2mrad.
基金Supported by the National Science and Technology Major Project(No 2010ZX04013)the National High Technology Research and Development Program of China under Grant No 2011AA030201,the Shanghai Rising-Star Program(No 09QB1401700)the Natural Science Foundation(No 60908011)。
文摘In order to increase the power fraction of the central lobe in the coherent beam combination of lasers in an array,the effects of the distance factor of near-field distribution on far-field interference patterns are calculated and demonstrated experimentally.An improved beam array of interwoven distribution is demonstrated to enable the power in the central lobe to reach 41%.An optimized mirror array is carefully designed to obtain a high duty ratio,which is up to 53.3% at a high power level.By using these optimized methods and designs,the passive phase locking of eight Yb-doped fiber amplifiers with ring cavities are obtained,and a pleasing interference pattern with 87% visibility is observed.The maximum coherent output power of the system is up to 1066 W.
文摘高亮度、窄线宽光纤激光光源在相干通信、激光雷达、相干/光谱合成、高能粒子加速器、聚变点火和激光冷却等领域具有重大的研究价值和广阔的应用前景。然而,光纤中的非线性效应以及大模场光纤的模式不稳定（MI）效应是保证光谱纯度和光束质量的同时进行输出功率定标放大的主要限制因素,因此,采用创新技术手段突破这两个限制因素是现阶段窄线宽光纤激光的研究焦点,引起国内外主流研究机构的重点关注。最近,2015年,德国Jena大学实现了45 GHz线宽,输出功率2.3 k W的近衍射极限光纤激光,
