光阑约束超几何激光束的传输特性

基于广义惠更斯-菲涅耳衍射积分和圆孔光阑函数展开为有限复高斯函数之和的方法,导出了超几何激光束通过有圆孔光阑约束的近轴ABCD光学系统传输的近似解析表达式,并对其传输特征进行了数值计算和分析。研究结果表明,超几何激光束光强的分布及其衍射效应与光阑的孔径大小、传输的距离以及光束参数等因素密切相关。此外,文中采用的近似解析方法与直接利用衍射积分计算相比,具有更高的计算效率,可以大大节省计算机时。     

激光二极管线列阵与多模光纤列阵的光纤耦合

利用一段数值孔径(NA)较小的多模光纤作为一个低成本的微透镜,对激光二极管线列阵的大数值孔径方向准直,将激光二极管线列阵的输出光束耦合到多模光纤列阵中.激光二极管线列阵每个发光单元的光分别耦合到光纤列阵的单根光纤中.总的耦合效率和输出光功率分别为75%和15W.     

激光二极管线列阵与多模光纤列阵的光纤耦合

利用一段数值孔径(NA)较小的多模光纤作为一个低成本的微透镜,对激光二极管线列阵的大数值孔径方向准直,将激光二极管线列阵的输出光束耦合到多模光纤列阵中.激光二极管线列阵每个发光单元的光分别耦合到光纤列阵的单根光纤中.总的耦合效率和输出光功率分别为75%和15W.     

GaN resonant cavity light-emitting diodes for plastic optical fiber applications

The optical designs of resonant GaN light-emitting diodes (LEDs) have been determined for maximum extraction efficiency into typical plastic optical fiber of numerical aperture 0.5. An optimum extraction efficiency of 3.9% can be achieved for a practical resonant cavity LED (RCLED), taking account of current growth and processing considerations. The optimized device is a metal-active layer distributed Bragg reflector construction. Constructive interference effects from the top metal mirror are found to play the dominant role in efficiency enhancement. The extraction efficiency of an optimized resonant single-mirror LED is found to be 3.3%, indicating a small compromise in performance compared with the more complex RCLED structure.     

利用单透镜结构实现自由空间激光进入单模光纤的耦合研究

自由空间激光与光纤的高效耦合可大幅降低激光 能量损耗。基于高斯光束通过透镜的传输规律,分 析经过单透镜变换后的激光光束特性,即像方激光光束特性。对自由空间激光与单模光纤的 优化耦合进行研究。通过分析匹配单透镜参数对像方光束的影响, 选择单透镜合适焦距参数,实现激光与光纤参数的高效匹配,满足激光光束的像方腰斑小于 10 μm且数值孔 径小于0.12。通过实例,分析采用焦距为5mm的单透镜对780 nm空间激光到单模光纤的耦合效 率,结果表明自由空间激光到单模光纤的耦合效率高达90%。该耦合 系统结构简单,可实现激光由自由空间到至光纤的高效率传输。     

星地链路空间光至单模光纤耦合效率补偿特性研究

在入射光瞳面处针对星地激光链路中空间光至单模光纤耦合效率补偿特性进行了研究,依据星地下行链路特点,对星地下行链路光纤耦合效率模型进行分析。在此基础上,利用基于单模光纤后向传输模场为加权函数的加权孔径正交多项式,建立光纤耦合接收系统波前相位模式补偿理论模型,运用该理论模型,通过数值模拟对波前相位进行模式补偿,给出波前相位模式补偿下平均光纤耦合效率与接收孔径尺寸和相位补偿项数的变化关系,以及典型接收孔径下采取一定项数的波前相位补偿后光纤耦合效率概率分布,为基于光纤耦合接收方式的星地激光通信链路波前补偿系统设计提供一定理论参考。     

大功率半导体激光器光纤耦合模块的耦合光学系统

针对 8 0 8nm大功率 Ga As/ Ga Al As半导体量子阱激光器的远场光场分布特点 ,提出了与多模光纤耦合时对耦合光学系统的特殊要求 ,并根据低成本、实用化的要求设计制作了专用的耦合光学系统 ,对耦合光学系统的实际性能进行了测试 ,给出了耦合效率统计分布图、耦合偏差曲线和高低温可靠性实验结果 .用设计制作出的实用化耦合光学系统完成了输出功率 15— 30 W,光纤束数值孔径为 0 .11— 0 .2 2的半导体激光光纤耦合模块 ,模块的使用结果表明耦合光学系统稳定、高效、实用     

掺Yb3+双包层石英光纤的研制及其激光特性

用MCVD工艺加溶液掺杂法研制成功了大几何尺寸、大数值孔径内包层的掺Yb3+双包层石英光纤,内包层直径125μm,数值孔径达0.36.完成了包层抽运光纤激光器的初步实验,在波长1.06μm处获得220mW的激光输出,光-光转换效率为26%.     

Synchronous Parallel Optical I/O on CMOS: A Case Study of the Uniformity Issue

Short-range parallel optical interconnect between integrated circuits can alleviate bandwidth, power, and packaging density issues that are associated with low-latency high-bandwidth input-output over electrical interconnect. In this paper, we evaluate the option of using true source-synchronous signaling over optical interconnect with a large number of channels, reducing the substantial per-channel clock synchronization circuitry to one instance. We also look into dc-unbalanced signaling to remove the need for data coding. Uniformity across channels is key to the feasibility of such an approach. An actual 64-channel parallel optical interconnect setup at 1.25 Gb/s/channel is examined, and models for the performance and uniformity of the different constituent parts of the interconnect are drawn up. Major attention is given to the statistical modeling of the coupling efficiency between a vertical cavity surface emitting laser array and a multifiber connector. Although derived in the context of a uniformity study, the stochastic models and the modeling approach are valuable in their own right. In our case study, the usage of a common logic threshold across all channels, which is required for dc-unbalanced signaling, appears infeasible after all models are combined. Efficient true source-synchronous signaling turns out to be within reach in carefully designed systems.     

超高速光互连系统级封装技术前沿研究

光互连系统级封装技术是用光互连在封装尺度上代替铜互连,以突破目前芯片间通信低速度瓶颈。超高速光互连系统级封装的目标是开发出可集成光子收发器,并嵌入到现代尖端的系统级封装中(SiP)中,以提高并行计算系统的数据传输效率或速度。文章介绍了超高速光互连系统级封装关键技术及前沿研究情况,通过分析IMEC、Intel、BAE系统公司等研究机构的开发现状和技术发展路线,论述了光互连SiP关键技术的发展趋势。     

浸没式阵列激光扫描直写光刻

介绍一种以显微镜结构为基础的浸没式阵列激光扫描直写光刻系统的光路结构、有效焦深、自动调焦及曝光能量控制的原理和方法。实验系统的有效数值孔径(ENA)为1.83,使用的激光波长为355nm时,在实验室条件下得到的最细线条宽度为65nm。     

Optical I/O Technology for Tera-Scale Computing

This paper describes both a near term and a long term optical interconnect solution, the first based on a packaging architecture and the second based on a monolithic photonic CMOS architecture. The packaging-based optical I/O architecture implemented with 90 nm CMOS transceiver circuits, 1 × 12 VCSEL/detector arrays and polymer waveguides achieves 10 Gb/s/channel at 11 pJ/b. A simple TX pre-emphasis technique enables a potential 18 Gb/s at 9.6 pJ/b link efficiency. Analysis predicts this architecture to reach less than 1 pJ/b at the 16 nm CMOS technology node. A photonic CMOS process enables higher bandwidth and lower energy-per-bit for chip-to-chip optical I/O through integration of electro-optical polymer based modulators, silicon nitride waveguides and polycrystalline germanium (Ge) detectors into a CMOS logic process. Experimental results for the photonic CMOS ring resonator modulators and Ge detectors demonstrate performance above 20 Gb/s and analysis predicts that photonic CMOS will eventually enable energy efficiency better than 0.3 pJ/b with 16 nm CMOS. Optical interconnect technologies such as these using multi-lane communication or wavelength division multiplexing have the potential to achieve TB/s interconnect and enable platforms suitable for the tera-scale computing era.     

厄米-高斯光束通过含硬边光阑光学系统束宽传输近似解析方程

本文对厄米-高斯光束通过含光阑系统的聚焦特性作了详细研究.采用将硬边光阑窗口函数展开为有限个复高斯函数之和的方法,推导出了由环围功率法定义的束宽传输的近似解析方程,并用数值计算例研究了光学系统和光束参数对光束聚焦特性的影响.     

高低频技术结合计算复杂目标电磁散射

本文利用高频近似方法与低频数值方法相结合的混合方法计算二维开槽电大目标的散射。首先根据等效原理将目标散射场进行分解,分别采用迭代物理光学法和边界元法计算槽缝填充的电大目标和槽缝散射,并应用广义网络原理和互易定理处理口径耦合问题。数据结果表明本文方法较高的精度和效率。     

猫眼光学系统的硬边光阑效应研究

采用矩阵分解以及将硬边光阑窗口函数展开为复高斯函数叠加的方法,研究了高斯光束猫眼光学系统后的光阑效应;通过数值计算,分析了激光的反射规律.研究表明,入射光束束腰距离猫眼光学系统越远,光学系统的光阑效应越大;调整合适的正离焦量,可以使猫眼光学系统回波光强更高.理论分析和数值计算对猫眼系统的研究具有一定的参考意义.     

激光二极管光束经光阑整形：耦合效率与波差分析

对激光二极管光束经光阑整形的方法进行了理论与数值分析,给出了光能耦合效率和波象差的数值计算结果。所得结论与数据有益于激光二极管光学系统的设计。     

部分相干修正贝塞尔-高斯光束通过光阑的传输

为了对部分相干修正贝塞尔-高斯光束通过有硬边光阑近轴ABCD光学系统的传输进行研究,采用将硬边光阑窗口函数展开为有限个复高斯函数之和的方法,得到了近似的解析传输公式.以部分相干修正贝塞尔-高斯光束在有光阑情况下自由空间的传输为例作了数值计算,对所得解析公式的计算误差和适用范围进行了讨论.结果表明,用该方法可快速、解析地研究部分相干修正贝塞尔-高斯光束通过圆孔光阑自由空间的传输特性,分析菲涅耳数、截断参数对其光束经光阑后光强分布的影响.     

Design of 20 W fiber-coupled green laser diode by Zemax

We represent a design of a 20 W, fiber-coupled diode laser module based on 26 single emitters at 520 nm. The module can produce more than 20 W output power from a standard fiber with core diameter of 400 μm and numerical aperture (NA) of 0.22. To achieve a 20 W laser beam, the spatial beam combination and polarization beam combination by polarization beam splitter are used to combine output of 26 single emitters into a single beam, and then an aspheric lens is used to couple the combined beam into an optical fiber. The simulation shows that the total coupling efficiency is more than 95%.     

Design limitations of highly parallel free-space opticalinterconnects based on arrays of vertical cavity surface-emitting laserdiodes, microlenses, and photodetectors

We utilize a novel diffraction formalism to study the crosstalk effect in a highly parallel free-space optical interconnect based on two-dimensional arrays of surface-emitting laser diodes, microlenses, and photodetectors. The diffraction induced crosstalk between adjacent laser diodes in each detector to the system limitations is investigated. Optimum design rules and formulas are given for the first time, to include the relation of channel packaging density and interconnect length to the design parameters of the optical interconnect components. The design formulas developed here yield an optimum detector size and indicate a tradeoff between channel packaging density and interconnect length. The feasibility of such a free-space interconnect with a channel packaging density of 3460 channels/cm² and 2.0 cm interconnection length is determined using typical parameters of detector radius from ~5 to ~45 μm, lens radius of 85 μm, and laser diode radius of ~5 pm operating at wavelength 0.67 pm for signal-to-noise ratio above 17 dB. Some experiments were conducted to measure the diffraction induced crosstalk and optical link efficiency     

Prismatic Coupling Structure for Intrachip Global Communication

Metal wires for global communication on integrated circuits have become problematic as device integration densities scale with rapid advancements in CMOS technology. They may not be able to deliver the growing bandwidth requirements of future microprocessors. Optical interconnect technologies may provide a solution to meet this challenge and extend Moore's law. In this paper, a novel guided-wave optical interconnect fabric aiming to replace the slow global metal interconnections is proposed and analyzed. The reflection-mode multiple-quantum-well-modulator-based optical interconnection approach is projected to achieve high coupling efficiency and be compatible with standard CMOS processes. The key notion is a prismatic coupling structure that is embedded in the optical waveguide and therefore has a very small footprint in the circuit. Ray-trace and finite-difference time-domain simulation results predict high coupling efficiency of this structure.