Characteristics of 980/1550 nm WDM coupler based on planar curved waveguides

A wavelength division multiplexer (WDM) for 980/1550 nm based on planar curved waveguide coupler (CWC) is proposed. Compared with conventional parallel straight waveguide coupler (SWC), this structure has more flexibility with two variable parameters of bending radius R and minimum edge-to-edge spacing do, which are the two main parameters for the splitting ratio of coupler and decrease the complexity of device design and fabrication. Based on coupled mode theory (CMT) and waveguide theory, R and do of the WDM CWC are designed to be R = 13.28 m and d(0) = 4.39 mu m. The contrast ratio (CR) and insertion loss (IL) for 980 and 1550 nm are CR1 = 24.62 dB, CR2 = 24.56 dB and IL1 = 0.014 dB, IL2 = 0.015 dB, respectively. The 3D beam propagation method (BPM) is used to verify the validity of the design result. The influence of R and d(0) variations on the device performance is analyzed. For CR > 20 dB, the variation ranges of R and d(0) should be within -0.10 to +0.44 m and -0.05 to + 0.02 mu m, respectively. (c) 2006 Elsevier GmbH. All rights reserved.

980 nm 抽运下Yb-Tm-Ho 三掺氟磷酸盐玻璃的2 μm 荧光性质

The thermal stability, 2 μm fluorescence properties and energy transfer mechanism in Ho³⁺ doped fluorophosphate glass sensitized by Yb³⁺ and Tm³⁺ were investigated. The characteristic temperatures, absorption spectrum and fluorescence spectrum of the glass sample were measured. ΔT calculated from the characteristic temperatures shows that the thermal stability of fluorophosphate glass is better than fluoride glass. According to the absorption spectrum, several spectroscopic parameters of the glass sample, such as Judd-Ofelt parameters and spontaneous transition probability were calculated and compared with other glass hosts. The largest spontaneous transition probability for Ho³⁺:⁵ I7&rarr⁵I8 transition in fluorophosphate glass which is 78.48 s^-1 indicates that fluorophosphate glass is an appropriate base glass to achieve 2 m fluorescence. From the fluorescence spectrum of the glass sample, the extremely strong 2.0 μm fluorescence intensity is observed, which is higher than the intensity of 1.8 μm fluorescence, showing that Ho³⁺ ions sensitized by Yb³⁺ and Tm³⁺ is efficient. Meanwhile, the absorption sections and emission sections of Yb³⁺, Tm³⁺ and Ho³⁺ were calculated and the pumping scheme and energy transfer mechanism among Yb³⁺, Tm³⁺ and Ho³⁺ are discussed. The study indicates that Yb-Tm-Ho tri-doped fluorophosphate glass is a significant sensitization glass system under 980 nm excitation for 2 μm applications.

High power 980 nm Al-free strained quantum-well lasers for erbium-doped fiber amplifiers

In this paper, we reported on the fabrication of 980 nm InGaAs/InGaAsP strained quantum-well (QW) lasers with broad waveguide. The laser structure was grown by low-pressure metalorganic chemical vapor deposition on a n(+)- GaAs substrate. For 3 mu m stripe ridge waveguide lasers, the threshold current is 30 mA and the maximum output power and the output power operating in fundamental mode are 350 mW and 200 mW, respectively. The output power from the single mode fiber is up to 100 mW, the coupling efficiency is 50%. We also fabricated 100 mu m broad stripe coated lasers with cavity length of 800 mu m, a threshold current density of 170 A/cm(2), a high slope efficiency of 1.03 W/A and a far-field pattern of 40 x 6 degrees are obtained. The maximum output power of 3.5 W is also obtained for 100 mu m wide coated lasers. (C) 2000 Elsevier Science B.V. All rights reserved.

High-performance 980-nm quantum-well lasers using a hybrid material system of an Al-free InGaAs-InGaAsP active region and AlGaAs cladding layers grown by metal-organic chemical vapor deposition

We report on the material growth and fabrication of high-performance 980-nm strained quantum-well lasers employing a hybrid material system consisting of an Al-free InGaAs-InGaAsP active region and AlGaAs cladding layers. The use of AlGaAs cladding instead of InGaP provides potential advantages in flexibility of laser design, simple epitaxial growth, and improvement of surface morphology and laser performance. The as-grown InGaAs-InGaAsP(1.6 eV)-AlGaAs(1.95 eV) lasers achieve a low threshold current density of 150 A/cm(2) (at a cavity length of 1500 mu m), internal quantum efficiency of similar to 95%, and low internal loss of 1.8 cm(-1). Both broad-area and ridge-waveguide laser devices are fabricated. For 100-mu m-wide stripe lasers with a cavity length of 800 Irm, a slope efficiency of 1.05 W/A and a characteristic temperature coefficient (T-0) of 230 K are achieved. The lifetime test demonstrates a reliable performance. The comparison with our fabricated InGaAs-InGaAsP(1.6 eV)-AlGaAs(1.87 eV) lasers and Al-free InGaAs-InGaAsP (1.6 eV)-InGaP lasers are also given and discussed. The selective etching between AlGaAs and InGaAsP is successfully used for the formation of a ridge-waveguide structure. For 4-mu m-wide ridge-waveguide laser devices, a maximum output power of 350 mW is achieved. The fundamental mode output power can be up to 190 mW with a slope efficiency as high as 0.94 W/A.

Uncooled Submarine Pump Laser Module at 980 nm

We present a new generation 980 nm submarine pump module that consists of a hermitically sealed 8-pin ceramic MiniDIL package without thermo-electric cooler.

980 nm半导体激光器可靠性的研究现状分析

本文介绍了提高980 nm半导体激光器可靠性的几种方案，并做了综合评述。进一步介绍了离子辅助镀膜技术在提高980 nm激光器可靠性方面的应用。

ECR plasma CVD法淀积980 nm大功率半导体激光器端面光学膜技术

介绍了电子回旋共振等离子体化学气相沉积(简称ECR plasma CVD)法淀积980nm大功率半导体激光器两端面光学膜的工艺条件，探索了膜系监控的方法和优越性，讨论了这种淀积方法的优点和淀积的光学膜的优良特性。

High Efficiency Al-Free 980 nm InGaAs/ InGaAsP/ InGaP Strained Quantum Well Lasers

于2010-11-23批量导入

High power 980 nm InGaAs/AlGaAs strained quantum well lasers

于2010-11-23批量导入

980 nm InGaAs应变量子阱激光器和掺铒光纤放大器用泵浦源

利用分子束外延技术研制出了高质量InGaAs/GaAs应变量子阱材料及量子阱激光器。在室温和10 K温度下,应变量子阱材料的光荧光峰值半宽分别为32 meV和.4 meV,宽接触激光器的阈值电流密度低达140 A/cm~2。脊形波导窄条形量子阱激光器的阈值电流和微分量子效率分别为15 mA和0.8 W/A,线性输出功率大于120 mW,基横模输出功率可达100 mW。InGaAs应变量子阱激光器和单模光纤进行了耦合其组合件出纤光功率典型值为40 mW,最大值可达60 mW,显示出了高的基横模输出功率和高的耦合效率。其组合件在40 mW下,中心发射波长在977 nm,成功地研制出适于掺铒光纤放大器用的应变量子阱激光器泵浦源。

High power 980 nm Al-free strained quantum-well lasers for erbium-doped fiber amplifiers

In this paper, we reported on the fabrication of 980 nm InGaAs/InGaAsP strained quantum-well (QW) lasers with broad waveguide. The laser structure was grown by low-pressure metalorganic chemical vapor deposition on a n(+)- GaAs substrate. For 3 mu m stripe ridge waveguide lasers, the threshold current is 30 mA and the maximum output power and the output power operating in fundamental mode are 350 mW and 200 mW, respectively. The output power from the single mode fiber is up to 100 mW, the coupling efficiency is 50%. We also fabricated 100 mu m broad stripe coated lasers with cavity length of 800 mu m, a threshold current density of 170 A/cm(2), a high slope efficiency of 1.03 W/A and a far-field pattern of 40 x 6 degrees are obtained. The maximum output power of 3.5 W is also obtained for 100 mu m wide coated lasers. (C) 2000 Elsevier Science B.V. All rights reserved.

Controllable Red, Green, Blue (RGB) and Bright White Upconversion Luminescence of Lu2O3:Yb3+/Er3+/Tm3+ Nanocrystals through Single Laser Excitation at 980 nm

Lu2O3:Yb3+/Er3+/Tm3+ nanocrystals have been successfully synthesized by a solvothermal process followed by a subsequent heat treatment at 800 degrees C. Powder X-ray diffraction, transmission electron microscopy, upconversion photoluminescence spectra, and kinetic decay were used to characterize the samples. Under single-wavelength diode laser excitation of 980 nm, the bright blue emissions of Lu2O3:Yb3+, Tm3+ nanocrystals near 477 and 490 nm were observed due to the (1)G(4)-> H-3(6) transition of Tm3+. The bright green UC emissions of Lu2O3:Er3+ nanocrystals appeared near 540 and 565 nm were observed and assigned to the H-2(11/2)-> I-4(15/2) and S-4(3/2)-> I-4(15/2) transitions, respectively, of Er3+. The ratio of the intensity of green luminescence to that of red luminescence decreases with an increase of concentration of Yb3+ in Lu2O3:Er3+ nanocrystals.

Further analysis of indentation loading curves: Effects of tip rounding on mechanical property measurements

The effects of indenter tip rounding on the shape of indentation loading curves have been analyzed using dimensional and finite element analysis for conical indentation in elastic-perfectly plastic solids. A method for obtaining mechanical properties from indentation loading curves is then proposed. The validity of this method is examined using finite element analysis. Finally, the method is used to determine the yield strength of several materials for which the indentation loading curves are available in the literature.

运动无力场中的等离子体状况

<正> 在太阳活动区以及磁层和某些等离子体彗星中的磁场位形大多是无力场。无力场在太阳物理和空间物理中是常遇到的。我们经常通过无力场模型对客体进行理论分析和处理,然后与观测的结果进行比较。Gold和Hoyle最早提出太阳黑子磁场中的磁力线的扭绞特性。以后,人们用静力学的关系定量地计算了磁场与扭转过程的关系;开始是势场的磁场位形通

球墨铸铁材料对激光的吸收率

球墨铸铁因其优良性能而被广泛用作模具材料。对球墨铸铁冲压模具的激光表面处理已成为改善其耐磨性、提高使用寿命的重要方法。一定激光参量下吸收率的大小又直接影响到表面处理的质量。因此，确定球墨铸铁材料对激光的吸收率十分必要。通过热电偶测温，计算机数据采集系统进行定点温度采集，并结合数值模拟方法，对吸收率进行了标定，即首先根据预置的吸收率计算，预测被测点处的温度响应，并与实测响应比较，不断修正吸收率值，使预测温度响应和实验值吻合，由此获得吸收率。采用这种方法获得了球墨铸铁材料在大气条件下对激光的吸收率为23．3％。为激光处理球墨铸铁材料时工艺参量的选择和优化提供了一定参考。