激光二极管抽运下铥/镱共掺碲镓酸盐玻璃光谱特性研究

研究了808 nm和977 nm激光二极管抽运下铥/镱共掺TeO₂-Ga₂O₃-R₂O(R=Li，Na，K)玻璃光谱特性.利用Judd-Ofelt 理论计算了Tm³⁺离子在碲镓酸盐玻璃中自发辐射跃迁概率、荧光分支比和辐射寿命等光谱参数.在977 nm激光二极管抽运下，观测到Tm³⁺/Yb³⁺共掺碲镓酸盐玻璃很强的476 nm上转换蓝光(¹G₄→³H₆)和较弱的650 nm上转换红光(¹G₄→³H₄和³F_2，3→³H₆).分析表明476 nm蓝光发射为三光子吸收过程，650 nm红光发射为双光子和三光子混合吸收过程；而在808 nm激光二极管抽运下，玻璃上转换蓝色荧光为双光子吸收过程.实验发现，随着碱金属离子半径的增大，977 nm激光二极管抽运下蓝光上转换发光强度增强，而用808 nm激光二极管抽运蓝光上转换发光无明显的变化. 关键词： 碲镓酸盐玻璃 铥镱共掺 Judd-Ofelt 理论 上转换     

掺Yb3+双包层光纤激光器实验中的荧光分析

在研究掺Yb3+光纤激光器的实验中,发现伴生有可见区的荧光,用光谱仪测量发现该可见区荧光的波长分别为639.4 nm,520.7 nm,487 nm和474.8 nm,通过对比分析掺Yb3+光纤中杂质的能级结构,发现伴生的红、绿、蓝荧光由Yb3+与Pr3+合作产生,其荧光过程是由于Yb3+离子的能量转移给Pr3+,由Pr3+受激辐射产生的红、绿、蓝荧光.实验结果表明:掺Yb3+双包层光纤吸收泵浦光后产生的荧光是上转换的,这会导致光纤激光器激光能量转换效率的降低.     

Upconversion Spectrum of Tm-doped Fiber Pumped by Multiwavelengths from 760 nm to 810 nm

１．ＩｎｔｒｏｄｕｃｔｉｏｎＡｐｐｌｉｃａｔｉｏｎｓｉｎｏｐｔｉｃａｌｄａｔａｓｔｏｒａｇｅ，ｃｏｌｏｒｄｉｓｐｌａｙｓａｎｄｂｉｏｍｅｄｉｃａｌｉｎｓｔｒｕｍｅｎｔｓｈａｖｅｍｏｔｉｖａｔｅｄｉｎｔｅｎｓｅｉｎｔｅｒｅｓｔｉｎｔｈｅｓｏｌｉｄｓｔ...     

掺Tm3+石英光纤中频率上转换产生可见光的实验研究

报道了实验研究连续锁模1053nmNd:YLF激光泵浦的掺Tm³⁺石英光纤中可见光区的频率上转换过程.测量了可见荧光光谱,并用Tm离子的分步三光子吸收过程解释了可见光频率上转换现象.     

掺Yb3+双包层光纤激光器中频率上转换产生可见光的实验研究

报道了激光二极管阵列泵浦的双包层掺Yb3+光纤激光器中频率上转换产生可见光的现象,对可见光区的光谱进行了测量,发现该上转换过程包括倍频效应和稀土离子间的合作发光效应,并对频率上转换的通道进行了分析.     

Monolithic fluoride-fiber laser at 1480 nm using fiber Bragg gratings

We report what we believe is the first monolithic fluoride-fiber laser making use of fiber Bragg gratings written directly in the doped fluoride-fiber core. The Tm(3+):ZBLAN fiber laser is upconversion pumped at 1070 nm and emits at 1480 nm. Using two different all-fiber cavities, we observed a threshold as low as 75 mW and a conversion efficiency of up to 40% with respect to launched pump power.     

两种新型有机染料的双光子上转换特性研究

通过对两种新型有机染料上转换材料CEASP-Ce与CEASPI的测试,研究了它们的双光子吸收、频率上转换特性.实验利用930 nm的红外激光泵浦两种染料溶液可得到 610 nm左右的上转换荧光.当提高浓度时,会得到方向性好、强度高、窄线宽的放大自发辐射（ASE）.通过对两种染料双光子光谱及上转换效率的比较,考察稀土离子对于有机物双光子上转换过程的影响.     

Multi-wavelength erbium-doped fiber laser using four-wave mixing effect in doped fiber

We demonstrate a multi-wavelength erbium-doped fiber laser (EDFL) using erbium gain and four-wave mixing (FWM) effect in a piece of erbium-doped fiber (EDF) with high erbium ion concentration. The EDF has a pump absorption rate of 24.6 dB/m at 979 nm and is bi-directionally pumped by 980-nm laser diodes. FWM effect redistributes the energy of different oscillating lines and causes multi-wavelength operation. The laser generates more than 22 lines of optical comb with a line spacing of approximately 0.10 nm at the 1569-nm region using only 1.5-m-long EDF.     

6.1 W single frequency laser output at 1645 nm from a resonantly pumped Er:YAG nonplanar ring oscillator

A monolithic 1645 nm Er:YAG nonplanar ring oscillator (NPRO) resonantly pumped by a 1532 nm fiber laser is demonstrated. For reducing the energy-transfer upconversion effect, a 0.5% doped Er:YAG nonplanar crystal was used. An up to 6.1 W single frequency laser output at 1645 nm was obtained, with a slope efficiency of 55.2% and an optical efficiency of 48.0%. The linewidth of the Er:YAG NPRO was 14.4 kHz.     

Diode-pumped 1018-nm ytterbium-doped double-clad fiber laser

We report a 1 018-nm ytterbium-doped double-clad fiber laser pumped by 970-nm diode. A pair of fiber Bragg gratings with reflectivities of 99.9% and 9% at a center wavelength of 1 018.9 nm are employed as cavity mirrors. The ytterbium-doped double-clad fiber is a 2.6-m-long Liekki fiber. Laser output power of 7.5 W at 1 018 nm is obtained under the pump power of 59.2 W. The overall slope efficiency of the fiber laser is about 16%. This low slope efficiency is mainly due to the incomplete absorption of the pump power.     

Phase-matched self-doubling optical parametric oscillator

We report a synchronously pumped intracavity frequency-doubled optical parametric oscillator that employs a single KTiOPO(4) crystal for both parametric generation and frequency doubling. Both nonlinear processes are phase matched for the same direction of propagation in the crystal. The parametric oscillator, pumped by a femtosecond Ti:sapphire laser at a wavelength of 745 nm, generates a green output beam at 540 nm with a 29% power conversion efficiency. Angle tuning in conjunction with pump wavelength tuning provides output tunability in the 530-585-nm range.     

Quantitative analysis of optical power budget of bismuth oxide-based erbium-doped fiber

We investigated optical power budget of Bi₂O₃-based erbium-doped fiber (BIEDF). Lateral spontaneous emissions and scattering laser powers in the BIEDF were measured quantitatively by using an integrating sphere. Compared with the power of amplified spontaneous emission and signal detected at the output fiber end, it was found that considerable powers were consumed by the laterally emitting lights. As an optically undetected loss limits power conversion efficiency (PCE) of the fiber amplifier, the effect of nonradiative decay from the termination level of pump excited state absorption (pump ESA) was estimated from decay rate analyses of the relevant levels. The nonradiative loss was comparable to amplified signal power in the BIEDF when pumped with a 980-nm LD. Nonradiative decay following cooperative upconversion (CUP) process is also discussed using rate equations analysis.     

Laser-diode-pumped 1319-nm monolithic non-planar ring single-frequency laser

Single-frequency 1319-nm laser was obtained by using a laser-diode-pumped monolithic Nd:YAG crystal with a non-planar ring oscillator (NPRO). When the NPRO laser was pumped by an 800-μm fiber coupled laser diode, the output power of the single-frequency 1319-nm laser was 220 mW, and the slope efficiency was 16%. With a 100-μm fiber coupled diode laser pumped, 99-mW single-frequency 1319-nm laser was obtained with a slope efficiency of 29%.     

Enhancement of upconversion luminescence of YAlO3:Er3+ by Gd3+ doping

The upconversion luminescences of YAlO3:Er3+ phosphor co-doping with different Gd3+ concentrations are investigated under the excitation of 980- and 532-nm diode lasers. A near ultraviolet upconversion emission at 410 nm is observed in YAlO3 under 532-nm excitation. Moreover, the inactive Gd3+ ions can improve the upconversion intensity efficiently in a certain range of concentration. Under 980-nm excitation, the visible upconversion emissions at 546 and 646 nm are enhanced by about 10 and 8 times at the Gd3+ concentration of 40%, respectively. The upconversion emission at 410 nm under 532-nm excitation is also enhanced by 7 times. The substitution of Gd3+ ions for Y3+ sites changes the local symmetry of Er3+, leading to the improvement of upconversion efficiency.     

Modelling of Threshold and Extraction Efficiency in Pr3+ ZBLAN Upconversion Fibre Lasers Using Two-Photon Pumping

We model the steady-state threshold and extracted power of a two-photon incoherently pumped upconversion fibre laser. Our threshold analysis is entirely analytic, and along with this derivation we obtain an analytic threshold cutback formula. This takes a particularly simple form when the ground state pump absorption follows exponential absorption. We also numerically simulate the extracted laser power. The experiment which we simulate is upconversion in Pr³⁺ doped ZBLAN fibre lasing at 491 nm and pumped with 1017 nm and 835 nm diode lasers. Our formulas and simulations are mutually consistent and agree with the experiment to within 10%.     

Demonstration of multi-Watt all-fiber superfluorescent source operating near 980 nm

The superfluorescent Yb-doped fiber source operating near 980 nm is studied. The design requirement is theoretically discussed aiming to suppress the amplified spontaneous emission around 1030 nm in the 980-nm superfluorescent fiber source. Based on the theoretical study, a multi-Watt, all-fiber, bi-directional, pumped, superfluorescent source operating near 980 nm is designed and experimentally demonstrated for the first time, to the best of our knowledge. The recorded 8.38-W combined output power is obtained with a 3-dB bandwidth about 3.5 nm. The power scaling of the 980-nm superfluorescent fiber source is limited by the parasitic laser oscillation.     

普通单模石英光纤中频率上转换过程的研究

介绍了在普通通讯用单模ＧｅＯ２／ＳｉＯ２石英光纤中从近红外到可见光的频率上转换过程。利用１．３１３μｍ的调Ｑ锁模Ｎｄ：ＹＬＦ激光脉冲泵浦单模石英光纤，产生了５８８ｎｍ的黄光，峰值功率达２０Ｗ，对应０．０９％的转换效率。     

High-power superfluorescent source with a side-pumped Yb-doped double-cladding fiber

A compact supe uorescent source based on an Yb-doped double-cladding fiber amplifier is described. The packaged amplifier is pumped at 975 nm by side-coupling emission from a 2.0-W broad-stripe laser diode through an imbedded V groove. The fiber source generates 485 mW of broadband emission centered at 1055 nm with a 41-nm FWHM flat power spectrum.     

Ytterbium-sensitized thulium-doped fiber laser with a single-mode output operating at 1900-nm region

A single-mode laser is demonstrated using a newly developed double-clad thulium-ytterbium-doped fiber (TYDF) in a linear cavity formed by two fiber Bragg gratings (FBGs). The YTF used is drawn from a D-shape preform fabricated using the modified chemical vapor deposition and solution doping technique. The laser is operated at 1 901.6 nm via the transition of thulium ions from 3F4 to 3H6 with the assistance of ytterbium to thulium ion energy transfer. The efficiencies of the laser are 0.71% and 0.75% at 927- and 905-nm multimode pumping, respectively. The thresholds of the launched pump power for 927- and 905-nm pumping are 1 314 and 1 458 mW, respectively. A 7-mW output is obtained at a 905-nm pump power of 2 400 mW.     

Cu:KNSBN晶体中复色光自泵浦相位共轭猝灭实验及其理论解释

当用５１４.５ｎｍＡｒ^＋激光束入射到掺Ｃｕ的ＫＮＳＢＮ晶体中时，观察到典型的猫型自泵浦相位共轭，而当用５１４.５和４８８ｎｍＡｒ^＋激光束共线入射到该晶体中时，观察到自泵浦相位共轭猝灭现象．对这一现象给出了一个理论解释 关键词：