1.47 /spl mu/m Tm/sup 3+/:ZBLAN fibre laser pumped at 1.064 /spl mu/m

A large core area (1257 /spl mu/m/sup 2/) Tm/sup 3+/-doped ZBLAN fibre laser operated at 1.47 /spl mu/m is demonstrated. The pump source is a Nd:YAG laser operated at 1.064 /spl mu/m. A laser output power of 1.56 W continuous wave was obtained for 5.2 W of launched pump power. The slope efficiency with respect to the launched pump power was measured to be 33%.     

Efficient cladding-pumped Tm-doped silica fibre laser with highpower singlemode output at 2 μm

Continuous-wave operation of a double-clad Tm-doped silica fibre laser at 2 μm pumped by two beam-shaped diode bars, yielded an output power of 14 W in a singlemode (M²<1.1)beam for 36.5 W of launched pump power at 787 nm. The slope efficiency with respect to launched diode power was ~46%     

Ytterbium-doped large-core fibre laser with 272 W output power

A highly efficient cladding-pumped Yb-doped large-core fibre laser, generating up to 272 W of continuous-wave output power at 1.08 /spl mu/m with a beam quality (M/sup 2/) of 3.2, is reported. The slope efficiency was 83% with respect to the launched pump power. No saturation (roll-off) was observed in output power with increasing pump power.     

High-power broadly tunable erbium-doped silica fibre laser

A Ti:sapphire laser at 980 nm has been used to pump a grating-tuned erbium-doped silica fibre laser. 540 mW launched pump power produces up to 270 mW tunable output near 1.55 mu m, with more than 250 mW obtainable from 1.52 to 1.57 mu m.<>     

Ytterbium-doped large-core fibre laser with 1 kW of continuous-wave output power

A ytterbium-doped fibre laser with up to 1 kW of continuous-wave output power at 1.09 /spl mu/m with a slope efficiency of 80% and a good beam quality (M/sup 2/=3.4) is reported. The fibre was pumped by two diode-stack sources launched through opposite ends. No undesirable roll-over was observed in output power with increasing pump power.     

Efficient upconversion pumping at 1.064 mu m Tm/sup 3+/-doped fluoride fibre laser operating around 1.47 mu m

1.064 mu m upconversion pumping was used to operate a highly efficient CW and Q-switched thulium (Tm/sup 3+/)-doped fluoride fibre laser at around 1.47 mu m. The maximum CW output power was 100 mW for a launched pump power of 570 mW. The threshold power was 200 mW, the slope efficiency 27% and the wavelength width 20 nm. A peak power of 70 W was generated for Q-switching at a launched pump power of 300 mW.<>     

Power scaling of 2 /spl mu/m ytterbium-sensitised thulium-doped silica fibre laser diode-pumped at 975 nm

An ytterbium-sensitised thulium-doped silica fibre laser that generates up to 75 W of output power in the 2 /spl mu/m wavelength range when cladding-pumped by a 975 nm diode stack is reported. The slope efficiency is 32% with respect to the launched pump power and the beam quality factor (M/sup 2/) is 1.3.     

Erbium-ytterbium co-doped hollow optical fibre laser

An erbium-ytterbium co-doped hollow optical fibre (HOF) laser generating up to 2.5 W of output power in the 1550 nm spectral region with a power conversion efficiency of 26% with respect to the launched pump power is demonstrated. A significant reduction of ytterbium co-lasing at 1060 nm is observed with increasing core thickness in the HOF, which is believed to be correlated with the signal overlap factor at 1550 nm that increases as the core thickness increased.     

光纤光栅选频掺Yb3+光纤激光器

以波分复用器(WDM),光纤光栅和自行研制的掺Yb~(3+)单模光纤,采用新颖的全光纤连接方案,实现了1060nm窄线宽、线形腔激光器的成功运转。对不同长度掺镱光纤(YDF)所构成的激光器进行了实验研究,发现9m为最佳长度。入纤抽运阈值功率约为30mW,当入纤功率达到最大值42.8mW时,得到最大激光输出8.8mW,半宽<0.5nm,相对于入纤抽运功率的斜率效率为70.4％。     

Diode pumped operation of thulium doped fluoride fibre amplifiersuitable for first window systems

A fully connectorised diode laser pumped first window amplifier has been constructed, for the first time, around a thulium doped fluoride fibre. For a 780/806 nm combination of pump and signal wavelengths, small signal gains of 25-26 dB and gain efficiencies of 2.4 dB/mW have been achieved. In addition, output powers approaching +13 dBm are possible for a launched pump power of 31 mW, which corresponds to a conversion efficiency of around 650%     

New coupling method for GaAs-laser?fibre coupling

A new method for coupling a diode laser to an optical fibre is described. This uses a cylindrical glass fibre as a focusing element. Optical feedback from the fibre endface has been found to have an influence on the laser output power. As a result, the light power launched into a single-mode fibre was higher than that obtainable from the laser during normal operation.     

1 W single-transverse-mode Yb-doped double-clad fibre laser at 978nm

A novel all-glass Yb-doped double-clad fibre laser that emits over 1 W of single-transverse-mode output at 978 nm is described. This device is efficiently pumped with 2.5 W of launched power from a single 200 μm broad-area laser diode at 915 nm     

Pr3+-doped 1.3 μm fibre laser using direct coateddichroic mirrors

A 1.3 μm fibre laser consisting of a 1000 ppm (mol) Pr³⁺ -doped fluoride glass fibre with dichroic mirrors coated onto the fibre endfaces and an Nd-YLF pump laser is presented. The output mirror reflectivity R is calculated to be 50% at the lasing wavelength. Producing a maximum output power of 50 mW. The laser threshold and slope efficiency are 300 mW and 8%, respectively. The theoretically predicted values correspond with the experimental values     

Highly efficient CW cascade operation of 1.47 and 1.82 mu m transitions in Tm-doped fluoride fibre laser

The 1.475 mu m selfterminating transition in a thulium-doped fluorozirconate fibre has been operated CW with thresholds as low as 3.2 mW of launched pump power. Furthermore, by enforcing oscillation at 1.475 and 1.88 mu m simultaneously, output powers of approximately 130 and approximately 115 mW, respectively, have been observed for around 325 mW of launched pump power. These results correspond to slope efficiencies of 43 and 38% or photon conversion efficiencies of 82 and 92%, respectively, for the 1.475 and 1.82 mu m transitions.<>     

Laser diode-pumped holmium-doped fluorozirconate glass fiber laserin the green (λ~544-549 nm): power conversion efficiency, pumpacceptance bandwidth, and excited-state kinetics

The green (544-549 nm) Ho-doped fluorozirconate (ZBLAN) glass fiber laser, pumped in the red (λ~6;15 nm) by a high-power (~30 mW) InGaAlP laser diode or a ring dye-laser, has been characterized with regard to power conversion efficiency, fiber core-diameter and length, cavity output coupling, and pump acceptance bandwidth. Fibers doped with ~1200 ppm (by weight) of Ho and having core diameters of 1.7, 3, and 11 μm, and lengths ranging from 12.5 to 86 cm, have been studied in Fabry-Perot resonators having output couplings ranging from 1.545 to 96%. For a 1.7-μm core-diameter fiber, 21 cm in length, the threshold-launched pump power for the diode-pumped fiber laser is 1.9 and 3.5 mW for cavity output couplings of 1.5% and 24%, respectively. These values are the lowest for any upconversion-pumped fiber laser reported to date. Also, the noise and threshold-pumping power properties of the diode-pumped fiber laser are superior to those for its dye-laser-pumped counterpart. The highest laser slope efficiency (>22% with respect to launched pump power) was measured for a 3-μm core-diameter fiber and a cavity output coupling of 24%. The spectral interval over which the launched threshold pump power for this laser is <10 mW is almost 20 nm (637-656 nm). Studies of the fiber laser waveform as a function of pump power reveal competition for population between the ⁵S² and ⁵F₄ states and among the Stark sublevels of the ⁵F₄ manifold. Also, measurements of the output power on individual laser lines of the ⁵F₄, ⁵S₂→ ⁵I₈ (ground) transitions of Ho³⁺:ZBLAN as a function of pump power demonstrate the existence of a loss mechanism at the fiber laser wavelength, presumably due to absorption from ground or the ⁵I_y, ⁶S₂ or ⁵F₄ excited states of the ion     

1120nm窄线宽掺镱光纤激光器

为了获得窄线宽、高功率、长波长(相对于1030nm~1080nm)的1120nm光纤激光器,采用普通单模掺镱光纤和一对光纤布喇格光栅构建了该光纤激光器的谐振腔,为保证抽运光的完全吸收和避免非线性效应,对有源光纤的最佳长度进行了理论分析和实验验证。结果表明,激光器的阈值抽运功率为40mW、注入抽运功率为265mW时,激光器输出信号光功率35mW,光光转换效率为13.2%,激光器中心波长为1120.9nm,输出激光的谱线宽度为0.03nm。这种激光器的获得是因为采用了高反射率耦合输出光纤布喇格光栅、短谐振腔结构和低功率运转状态。该激光器可作为种子光注入光纤放大器。     

Repeaterless transmission with 62.9 dB power budget using a highly efficient erbium-doped fibre amplifier module

A 565 Mbit/s DPSK heterodyne transmission experiment has been demonstrated using a fibre post-amplifier. Over +12 dBm output powers were obtained in a both end pumping configuration for 35 mW total launched pump power, leading to a repeaterless link budget of 62.9 dB.<>     

All fibre laser system with 0.1 W output power in blue spectralrange

A ytterbium sensitised thulium-doped blue upconversion ZBLAN fibre laser pumped at 1065 nm by a high power, diode pumped, double clad fibre laser is demonstrated. With a pump power of 2.8 W at 1065 nm, a blue output power of 106 mW at 482 nm is achieved     

Gamma-ray induced pulsewidth broadening and power loss inmodelocked Er-doped fibre laser

A modelocked erbium-doped fibre laser (EDFL) exhibited a 9.7% decrease in its pump laser output power and pulsewidth broadening from 9.2 to 300 ps following a 10.14 kGy(Si) gamma-ray irradiation. A decrease in the EDFL intra-cavity power from the combined effects of the pump laser degradation, and colour centre induced absorption in the fibre segments and other EDFL components was responsible for the broadening and long recovery times required for restoration of modelocking     

977-nm all-fiber DFB laser

Three-level operation of a fiber distributed feedback (DFB) laser operating around 980 nm is demonstrated for the first time. The ytterbium-doped DFB laser shows a maximum slope efficiency of 61% and output power of 38.2 mW under a launched single-mode pump power of 150 mW at 910 nm. The efficiency of lasers with different coupling strengths and at different pump wavelengths is also investigated.