注入锁定激光器的边带锁频技术稳频系统优化分析

介绍了边带锁频技术稳频方法，推导出鉴频曲线，对稳频控制过程进行了分析．建立了注入锁定激光器的边带锁频技术稳频系统理论模型，讨论了相关参量对稳频效果的影响并且进行了优化．结果表明，增加入射光强，采用窄线宽的法布里一珀罗以及对法布里一珀罗进行高准确度温控都可以增强稳频效果．提出适用于注入锁定激光器的两种稳频方案并进行比较．

氟磷酸盐玻璃的应用研究进展

氟磷酸盐玻璃系统南于其特殊的光学性能和优良的机做与热学性能一直是特种光学玻璃材料领域的一个研究热点。总结了氟磷酸盐玻璃的分类及玻璃组分与其结构的关系，综述了氟磷玻璃在光学器件、高能高功率激光玻璃、光纤激光器、光纤放大器及上转换发光基质材料等领域上的应用，并对其未来的发展进行了展望。

新型掺铒离子氧氟碲酸盐玻璃的光谱性质

探求新的具有优良的热学和光学性能的基质玻璃系统，是获得具有宽带宽和增益平坦的掺Er^3＋光纤放大器（EDFA）的一种有效途径。制备了一种新型氧氟碲酸盐玻璃TeO2-BaF2-LaF3，并对其热学性能和光学性质进行了测试。应用乍得-奥菲尔特（Judd-Ofelt）理论计算了Er^3＋离子的J-O理论参量和荧光寿命r。探讨了氟化物的引入对碲酸盐玻璃结构的改变的影响，并分析了其对玻璃的热学性质和光学性质的影响。实验发现，获得的氧氟碲酸盐玻璃具有优良的热学稳定性（△T=156.6C），宽的荧光半峰全宽（72nm）

Infrared-to-visible upconversion emissions in Er3+ doped TeO2-based oxyhalide glasses

The fluorescence and up-conversion spectral properties of Er3+-doped TeO2-ZnO and TeO2-ZnO-PbCl2 glasses suitable for developing optical fiber amplifier and laser have been fabricate and characterized. Strong green (around 527-550 nm) and red (around 661 nm) up-conversion emissions under 977 nm laser diode excitation were investigated, corresponding to H-2(11/2), S-4(3/2), --> I-4(15/2) and F-4(9/2) --> I-4(15/2) transitions of Er3+ ions respectively, have been observed and the involved mechanisms have been explained. The dependence of up-converted fluorescence intensity versus laser power confirm that two-photons contribute to up-conversion of the green-red emissions. The novelty of this kind of optical material has been its ability in resisting devitrification, and its promising optical properties strongly encourage for their further development as the rare-earth doped optical fiber amplifiers and upconversion fiber laser systems.

掺铒碲酸盐玻璃的热力学稳定性和光谱性质的研究

分析了掺Er^3+碲酸盐玻璃的热力学稳定性能，研究了掺Er^3+碲酸盐玻璃的吸收和荧光光谱性质；应用Judd-Ofelt理论计算了碲酸盐玻璃中Er^3+离子的强度参数Ω(Ω2=4．79×10^-20cm^2,Ω4=1．52×10^-20cm^2，Ω6=0．66×10^-20cm^2)，计算了离子的自发跃迁几率，荧光分支比；应用McCumber理论计算了Er^3+的受激发射截面(σe=10．40×10^-21cm^2)、Er^3+离子^4I13／2→^4I15／2发射谱的荧光半高宽(FWHM=65．5nm)

Stability against crystallization and spectroscopic properties of Tm3+ doped fluorophosphate glasses

Fluorophosphate glasses with various content of Al(PO3)(3) were prepared. With the increment of Al(PO3)(3) content, density decreases while refractive index increases, and transition temperature, crystallization peak temperature and melt temperature increase which were suggested by differential scanning calorimetry. These glasses exhibit the best stability against crystallization with 7-9 mol'Yo Al(PO3)(3) content. Normalized Raman spectra were used to analyze structure and phonon state. The increment of Al(PO3)(3) content does not affect phonon energy but results in the augment of phonon density. Absorption spectra were measured. H-3(6) -> F-3(4) transition exhibits absorption at L band of the third communication window. Compared with the energy of Tm3+ excited states in other glass system, F-3(4) energy of Tm3+ in these glasses is considerable higher and H-3(4) energy is considerable lower, and it can be predicted that emission band of H-3(4) -> F-3(4) transition is close to the amplified band of gain-shift Tm3+ doped fiber amplifier. Analyses of Judd-Ofelt theory suggest when Al(PO3)(3) content is no more than 7 mol%, Judd-Ofelt parameters Omega(t) and the lifetime of H-3(4) energy level of TM3+ vary little with the increment of Al(PO3)(3) content, and when Al(PO3)(3) content is more than 7 mol%, Omega(2) and Omega(6) increase and radiative lifetime of H-3(4) energy level of Tm3+ drops sharply with the increment of Al(PO3)(3) content. (c) 2006 Elsevier B.V. All rights reserved.

稀土离子掺杂的多组分玻璃光纤

abstract {Rare earth ions doped multi-component glass fibers have important application in broad band fiber amplifier and up-conversion fiber lasers. In this paper, the mechanism and the progress of study on rare earth ions doped multi-component glass fibers in broad band fiber amplifier and up-conversion fiber lasers are introduced and reviewed. The questions and the applications of rare earth ions doped multi-component glass fibers in the future are also prospected. Based on the present research progress, it is suggested to further study the tellurite and bismuth glasses, which are used as fiber materials in broad band fiber amplifier. To up-conversion fiber laser, it is still need to further investigate novel glasses, which has low phonon energy and good physical and chemical properties.}

Spectroscopic properties of Er3+ doped TeO2-BaO (Li2O, Na2O)-La2O3 glasses for 1.5-mu m optical amplifiers

This paper reports on the optical spectroscopic properties and thermal stability of Er3+-doped TeO2-BaO (Li2O,NaO)-La2O3 glasses for developing 1.5-mu m fiber amplifiers. Upon excitation at 977 nm laser diode, an intense 1.53-mu m infrared fluorescence has been observed with a broad full width at half maximum (FWHM) of about 60 nm for the Er3+-doped TeO2-BaO (Li2O, Na2O)-La2O3 glass with 10 mol% of BaO. The calculated fluorescence lifetime and the emission cross-sections of the 1.53-mu m transition are 2.91 ms and similar to 9.97 x 10(-21) cm(2), respectively. It is noted that the gain bandwidth, a, x FWHM, of the TeO2-BaO-La2O3Er2O3 glass is about 600, which is significantly higher than that in silicate and phosphate glasses. Meanwhile, it is interesting to note that the TeO2-BaO-La2O3-Er2O3 glass has shown a high glass thermal stability and good infrared transmittance. As a result, TeO2-BaO (Li2O, Na2O)-La2O3 glass with 10 mol% of BaO has been considered to be more useful as a host for broadband optical fiber amplifier. (c) 2005 Elsevier B.V. All rights reserved.

Preparation and spectroscopic properties of Er3+-doped high silica glass fabricated by sintering nanoporous glass

A compact nonporous high silica (SiO2 % > 96%) glass containing 3400 ppm Er3+ ions, which was about ten times higher than that in Er-doped silica fiber amplifier (EDSFA), was synthesized by sintering porous glass immersed into erbium nitrate solution. The 1532 nm fluorescence has a FWHM (Full Width at Half Maximum) of 45 nm wider than that of EDSFA and possesses the glass with potential application in broadband fiber amplifiers. The Judd-Ofelt theoretical analysis reflects that Er3+ ions are located in a higher covalent environment which are comparable to those of aluminosilicate glass. (c) 2005 Elsevier B.V. All rights reserved.

Roteamento e alocação de comprimento de onda em redes WDM segundo algoritmo baseado em regras da natureza.

O surgimento de novos serviços de telecomunicações tem provocado um enorme aumento no tráfego de dados nas redes de transmissão. Para atender a essa demanda crescente, novas tecnologias foram desenvolvidas e implementadas ao longo dos anos, sendo que um dos principais avanços está na área de transmissão óptica, devido à grande capacidade de transporte de informação da fibra óptica. A tecnologia que melhor explora a capacidade desse meio de transmissão atualmente é a multiplexação por divisão de comprimento de onda ou Wavelength Division Multiplexing (WDM) que permite a transmissão de diversos sinais utilizando apenas uma fibra óptica. Redes ópticas WDM se tornaram muito complexas, com enorme capacidade de transmissão de informação (terabits por segundo), para atender à explosão de necessidade por largura de banda. Nesse contexto, é de extrema importância que os recursos dessas redes sejam utilizados de forma inteligente e otimizada. Um dos maiores desafios em uma rede óptica é a escolha de uma rota e a seleção de um comprimento de onda disponível na rede para atender uma solicitação de conexão utilizando o menor número de recursos possível. Esse problema é bastante complexo e ficou conhecido como problema de roteamento e alocação de comprimento de onda ou, simplesmente, problema RWA (Routing and Wavelentgh Assignment problem). Muitos estudos foram realizados com o objetivo de encontrar uma solução eficiente para esse problema, mas nem sempre é possível aliar bom desempenho com baixo tempo de execução, requisito fundamental em redes de telecomunicações. A técnica de algoritmo genético (AG) tem sido utilizada para encontrar soluções de problemas de otimização, como é o caso do problema RWA, e tem obtido resultados superiores quando comparada com soluções heurísticas tradicionais encontradas na literatura. Esta dissertação apresenta, resumidamente, os conceitos de redes ópticas e de algoritmos genéticos, e descreve uma formulação do problema RWA adequada à solução por algoritmo genético.

Simulador MATLAB para Sistemas Ópticos WDM Amplificados.

Neste trabalho é apresentado um simulador MATLAB para sistemas ópticos WDM amplificados baseado na solução das equações não lineares de Schrödinger acopladas, pelo método de Fourier de passo alternado. Este simulador permite o estudo da propagação de pulsos em fibras ópticas, considerando dispersão cromática, efeitos não lineares como automodulação de fase e modulação de fase cruzada e atenuação, prevendo também o emprego de amplificadores ópticos a fibra dopada com Érbio (EDFAs). Através de simulações numéricas, foi explorada a técnica de otimização do posicionamento de um EDFA ao longo de um enlace óptico, sem repetidores, que objetiva a redução dos custos de implantação de sistemas ópticos, seja pela diminuição da potência do transmissor ou pela relaxação da exigência de sensibilidade do receptor. Além disto, pode favorecer um aumento na capacidade do sistema, através do aumento do alcance ou da taxa de transmissão. A concordância dos resultados obtidos com os disponíveis na literatura confirmam a validade da técnica, bem como a versatilidade e robustez do simulador desenvolvido.

Diode laser pumped, KERR phase-shifting and switching of a diode laser signal in a small area optical fibre

In this paper authors report the first demonstration of a diode laser powered Kerr effect device, consisting of a single birefringent fiber, able to phase-shift and switch an optical signal generated by a second laser diode. They have obtained fast, stable phase-shifting of 90° in a single fiber, at a coupled pump power of only 20 mW. Using this phase shift to induce polarization switching with resultant gating, 25% modulation of the diode laser signal has been observed, with a detection limited-rise time of 10ns.

1.55-μm VCSEL transmission performance up to 20 Gb/s for access networks

We experimentally demonstrate for the first time 1.55μm vertical-cavity surface-emitting laser (VCSEL) transmission over 6.5 km single mode fiber (SMF) at 20 Gb/s for optical access networks. Characterization of the device is also investigated. © 2009 IEEE.

Orthogonal multipulse modulation for 64 Gigabit Fibre Channel

Real-time orthogonal multipulse modulation is demonstrated at 56 Gb/s with transmission over 500 m of single-mode fiber. Up to 2 dBo power budget advantage is predicted relative to alternatives such as PAM4. © 2013 OSA.

Orthogonal multipulse modulation for 64 gigabit fibre channel

Real-time orthogonal multipulse modulation is demonstrated at 56 Gb/s with transmission over 500 m of single-mode fiber. Up to 2 dBo power budget advantage is predicted relative to alternatives such as PAM4. © 2013 OSA.