870 mW blue laser emission at 480 nm in a large core thulium doped ZBLAN fiber laser

We report on high power 870 mW continuous wave stable laser operation at 480 nm in a 1000 ppm wt. Thulium doped multimode ZBLAN up-conversion fiber laser. The fiber is pumped by a wavelength of 1064 nm generated from diode-pumped Nd:YAG laser. A threshold of 550 mW and slope efficiency of 14% with respect to the incident pump power has been obtained. The related problem of photo-degradation associated with formation of color centers is reported. The transparency of the darkened fiber prior to the lasing operation is restored by circulating 514 nm through the fiber core. The time dependant oscillatory behavior of the emitted laser is also addressed.     

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.     

Yb(3+)-ring-doped fiber for high-energy pulse amplification

We report what is to our knowledge the first demonstration of pulse amplification in a cw-pumped fiber in which the doped gain medium has a ring shape surrounding a single-mode core. For a given pump power, ring doping reduces the gain and hence the power lost to amplified spontaneous emission. Thereby, a significantly larger amount of energy can be stored in the amplifier. Using an Yb(3+)-doped fiber pumped by 540 mW of power at 1000 nm, we measured 69 microJ of extracted pulse energy at 1047 nm, the highest value reported to date from a single-mode Yb(3+)-doped fiber. We predict that a fiber cladding pumped by a diode bar can produce pulse energies in excess of 1 mJ.     

Amplified spontaneous emission properties of a single mode Er3+-doped tellurite fiber

Spectral characteristics of the amplified spontaneous emission(ASE)from a novel single mode Er3+ doped tellurite fiber with D-type cladding is reported in this letter.When pumped at 980 nm,an ASE source that has nearly a 100-nm flat FWHM bandwidth is obtained with a fiber length of 30-60 cm. Variation of ASE spectra with pump powers and fiber lengths are measured.Output power up to 2.0 mW is obtained with a launched pump power of 660 mW.     

High power tandem pumping fibre amplifier

We demonstrate a high efficiency 1083 nm fibre amplifier tandem pumped by a 1030 nm fibre laser. The 1030 nm fibre laser is coupled into a 25 m long single clad ytterbium doped fibre via a high power wave division multiplexer to core pump the 1083 nm signal laser. An output power of 4.5 W and a power conversion efficiency of 76.6% are achieved without power-roll. The performance of the amplifier can be improved by optimizing the gain fibre length.     

Efficient special S-band ytterbium fiber laser emitting at 1012 nm and its application in tandem pumping

We presented the first demonstration of a special S-band Yb-doped fiber laser with a central wavelength of 1012 nm. By pumping common alumosilicate fiber doped with 974 nm laser diode, efficient lasing at 1012 nm was achieved with a maximal output power of 331 mW and 55% power conversion efficiency. We also built a fiber amplifier to validate the feasibility of the 1012 nm laser as the tandem pump source by boosting the 1064 nm C-band laser power up. The slope efficiency of the tandem-pumped fiber amplifier is 63%.     

镱铝共掺石英玻璃的制备及其发光特性的研究

提出了一种新的溶液掺杂与非化学气相沉积(non-chemical vapor deposition, NCVD)熔融相结合的方法制备稀土掺杂石英基玻璃,并采用该方法制备出组分为98SiO₂-0.5Yb₂O₃-1.5Al₂O₃wt%、折射率n_D =1.519和密度 ρ=2.62 g/cm³的镱铝共掺石英玻璃.经实验测试表明:它的 关键词： 镱铝共掺石英玻璃 溶液掺杂 发光特性 光子晶体光纤     

Optimization of the dimensions of an Yb(3+):ZBLANP optical fiber sample for laser cooling of solids

We propose a theoretical model for an optimized fiber structure for use in anti-Stokes laser cooling of solids. The sample is an optical fiber fabricated from a fluorozirconate glass ZBLANP with a core doped with Yb(3+) ions. The diameter of the fiber core is optimized to achieve the largest temperature change in the sample. It is shown that for each value of the pump power there is an optimized diameter of the fiber core, which permits the largest drop in the temperature of the sample.     

20 W single-mode Yb3+ -doped phosphate fiber laser

We report the demonstration of the first, to our knowledge, cladding-pumped continuous-wave Yb(3+)-doped phosphate-glass fiber laser. Phosphate hosts are of interest because they can be much more heavily doped than silica, and because of the possibility that they may have a higher photodarkening threshold. In an 84.6 cm double-clad fiber doped with 12 wt. % of Yb(2)O(3) and laser-diode pumped at 940 nm, nearly 20 W of single-mode 1.07 microm output power was generated with 60.2 W of absorbed pump power. The measured dependence of the output power on pump power is in excellent agreement with simulations.     

Investigation on stimulated Brillouin scattering characteristics in a highly doped Bismuth-based Erbium-doped fiber

Stimulated Brillouin scattering (SBS) characteristics in a 49 cm long highly doped Bismuth-based Erbium doped fiber (Bi-EDF) is investigated in the ring and linear cavity configurations. At Brillouin pump (BP) power of 6 dBm, the Brillouin laser peak power of the optimized ring Brillouin Erbium fiber laser (BEFL) is obtained at 23 dB higher than the peak power of the conventional linear cavity at an up shifted wavelength of 0.08 nm. This Bi-EDF ring cavity operates at nearly 1563 nm wavelength region, which is up-shifted by 0.08 nm from the Brillouin pump wavelength with the side mode suppression ratios (SMSR) of 29 and 23 dB in the forward and backward directions, respectively.     

15波长输出的布里渊掺铒光纤激光器

多波长布里渊掺铒光纤激光器是一种新型的多波长光纤激光器,其原理是利用受激布里渊增益和掺铒光纤的线性增益,可以在常温下得到波长间隔约为0．08nm(～10GHz)的多波长输出。报道的布里渊掺铒光纤激光器,在布里渊抽运功率为1．7mW、980nm抽运功率为300mW的情况下得到稳定的15个波长(间隔～10GHz)的输出,这种激光器用作光传感器、光谱分析仪以及密集波分复用系统的光源。实验发现,输出波长的个数随着980nm抽运功率的增大而增加。另外,布里渊掺铒光纤激光器的信号功率主要来自于掺铒光纤的增益,而布里渊增益对它的影响不大。     

国产光纤实现同带抽运3000W激光输出

同带抽运是目前实现高功率光纤激光器的有效手段.本文基于同带抽运方式,以国产25/250μm掺镱双包层光纤为增益光纤,构建了全光纤化的主控振荡器功率放大器.实验中采用的国产光纤是中国电子科技集团公司第四十六研究所采用化学气相沉积结合气相-液相复合掺杂工艺制备的,其Yb~(3+)离子的分布更均匀,吸收截面更大,吸收系数更高.实验中,在种子光功率为67.8 W、抽运总功率为3511 W的条件下,实现了3079 W的激光输出,斜效率为85.9%,光束质量M~2约为2.14,3dB带宽为1.4nm,这是目前基于国产光纤同带抽运方式实现的最高功率.理论和实验结果表明国产光纤制备技术不断成熟,已经具备承受高功率输出的能力.继续提高抽运功率,优化增益光纤长度,改良散热方式,国产光纤有望实现更高功率的激光输出.     

一种高效率的L波段掺铒光纤ASE宽带光源

利用双程双向泵浦单级掺铒光纤的结构实现高效率的L波段掺铒光纤放大自发辐射输出,同时选择1480nm半导体激光器作为泵浦源,高掺杂铒光纤为增益介质,通过优化铒光纤长度,获得了在1566-1604 nm（38 nm）,自发辐射谱功率高于－16 dBm,总输出功率13.7 dBm的L波段掺铒光纤放大自发辐射光源.该光源结构相比于双程前向泵浦结构的L波段掺铒光纤放大自发辐射光源,其泵浦效率从11.8%提高到23.4%.     

Comparisons of multi-wavelength oscillations using Sagnac loop mirror and Mach-Zehnder interferometer for ytterbium doped fiber lasers

A multiwavelength Ytterbium-doped fiber ring laser operating at 1030 nm region is demonstrated using a Sagnac loop mirror and a Mach-Zehnder interferometer. We report the Performance comparisons of multi-wavelength oscillations in Yb³⁺ doped fiber lasers (YDFL) with typical commercial ytterbium doped silica fibers. By adjusting the polarization controller (PC), a widely tunable laser range of 22 nm from 1030 nm to 1050 nm is obtained. The Mach-Zehnder interferometer (MZI) design has exhibited simplicity in the operation for controlling the smallest wavelength spacing compared to Sagnac loop mirror method. In our observations, the smallest achieved stable wavelength spacing in Sagnac loop mirror setup and MZI setup were 2.1 nm and 0.7 nm, respectively. In case of nine-wavelength operation with a MZI setup, the stability, Full Width at Half Maximum (FWHM) and side mode suppression ratio (SMSR) of laser lines are not affected by increasing pump power, While for above four wavelength operation, the laser stability with Sagnac loop mirror becomes worse specially for higher input pump power and the power fluctuation among the wave-lengths would be also slightly larger.     

利用光纤光栅的高功率掺镱光纤激光器

报道了利用一对光纤光栅作为双包层Yb^3 掺杂光纤激光器的谐振腔，激光二极管光纤模块(LD)进行了抽运，并采用锥形光纤实现了全光纤化结构，获得了高功率双包层光纤激光器。光纤光栅通常是用融接技术实现与双包层光纤的一体化连接的，采用的双包层光纤为内包层为梅花瓣形结构的掺Yb^3 离子的石英光纤，采用的抽运源为中心波长为970nm的半导体激光光纤输出模块，在抽运源电流达到2．4A时，获得了10．8W的光纤激光器单横模输出，输出波长1100．5nm，峰值半峰全宽(FWHM)为0．54nm，激光器斜效率为59％。     

基于环形芯光纤的超低差分模式增益涡旋光纤放大器

提出了一种基于环形芯铒离子部分掺杂光纤的涡旋光纤放大器。针对该掺铒光纤的放大特性,研究了光纤长度、掺铒浓度与抽运功率对信号模式增益特性的影响。研究结果表明,该光纤放大器能够支持22个轨道角动量模式稳定传输,且C波段(1530~1565 nm)所有信号模式增益大于23 dB,信噪比高于27 dB,差分模式增益小于0.015 dB。所提出的基于环形芯光纤的涡旋光纤放大器具有支持轨道角动量模式数量多、差分模式增益低、信噪比高的优势,对于OAM复用长距离传输系统中的在线放大具有重要参考价值。     

石英基掺Tm3+包层抽运光纤激光器

在MCVD车床上利用“湿法”掺杂方法研制出纤芯高掺Ge的石英基掺Tm³⁺光纤预制棒,采用侧面研磨和抛光工艺制成横截面为正六边形的光纤预制棒.经拉丝,内层涂覆低折射率材料后制成包层抽运光纤.测试其吸收谱,并对光纤参数进行优化.通过在光纤两端紫外写入光纤Bragg光栅,制成线形光学谐振腔,在工作波长793nm的激光抽运下,获得工作波长1947.1031nm、功率2.05W的激光输出.由此证明这种光纤具有优异的光学特性. 关键词： 3+光纤')" href="#">石英基掺Tm³⁺光纤 光纤Bragg光栅 包层抽运 光纤激光器     

Raman fiber laser improvement by using Yb3+-doped fiber

We report here the efficiency improvement in a fiber Raman laser by splicing to it short pieces of 10000-ppm Yb³⁺-doped fibers. The amplified spontaneous emission produced by the doped fiber started the stimulated Raman scattering earlier than the spontaneous scattering in the 350-m silica-fiber cavity. In the best case, when splicing to the cavity 127 cm of doped fiber, the pump threshold decreased from 2.9 down to 1.27 W, representing a 56% improvement. This power was close to the theoretical minimum of 1.25 W for very long fibers. The second stokes signal (1175 nm) was only present when the doped fibers were inserted. At 4-W pump, the non-doped cavity delivered 2 W of first stokes signal (1117 nm) that represent a 50% efficiency compared to ～3 W delivered (～75%) when a 34-cm doped fiber was inserted. This improvement is intended to reduce the cost of fiber Raman lasers because less powerful sources or shorter fibers are necessary to produce more stokes components.     

Tunable multiwavelength Brillouin-erbium ring-cavity fiber laser with short-length photonic crystal fiber

A multi-wavelength Brillouin-erbium ring-cavity fiber laser utilizing 2-m erbium doped fiber (EDF) and 70-m high nonlinear photonic crystal fiber (PCF) is proposed and demonstrated. The output characteristics and also the impacts of pump and Brillouin pump (BP) on the output spectra are investigated in detail. The output number and wavelength location of Brillouin lines are tunable by adjusting the power of 1465 nm pump and BP, and a 5-channel output within 11 nm (1551–1562 nm) tuning range is achieved by choosing appropriate pump power.     

A low-threshold multiwavelength Brillouin fiber laser with double-frequency spacing based on a small-core fiber

We demonstrate multiwavelength Brillouin fiber lasers (MWBFLs) with double-frequency spacing based on a small-core fiber (SCF) and a standard single-mode fiber (SMF), which have core diameters of 5 and 8.8 μm, respectively. Experimental results show that the SCF-based MWBFL exhibits a higher laser output power and a lower pump threshold. The output powers of the SCF-based MWBFL are > 1.4 times those of the SMF-based MWBFL. Moreover, the threshold power required to generate each channel of the SCF-based MWBFL is 59% that of the SMF-based MWBFL. When the same pump power of 180 mW is injected, the number of laser channels generated for the SCF-based MWBFL is 13, which is twice that generated for the SMF-based MWBFL. In addition, the SCF-based MWBFL exhibits good wavelength tunability from 1535 to 1565 nm and temporal stability over an hour.