面向SOI波导-单模光纤耦合的硅微透镜设计

硅光集成的优势在高速光电子领域不断凸显,被广泛应用于各种通信场景中。在硅基集成技术发展过程中,其面临的一个典型技术难点是硅波导与单模光纤的耦合。本文设计了波导边缘集成的硅微透镜结构,经BPM法(Beam Propagation Method)计算验证该结构可实现3μm厚SOI波导与纤芯直径86μm单模光纤90的近场耦合效率,具备高集成度、高耦合效率、多场景适用等优点。     

基于多模干涉波导结构的90°光混频器设计与制作

设计并制作了一种基于多模干涉波导(MMI)结构的InP基90°光混频器芯片,该芯片的波导层材料为InGaAsP,包层和衬底材料为InP,芯片的单模波导宽度设计为2.6μm,多模干涉波导的长度和宽度分别设计为844和20μm。采用三维光束传播法(3D BPM),仿真分析了波导材料折射率、厚度、宽度和长度的工艺误差容限,仿真结果表明在1 535～1 565 nm波长范围内所设计的光混频器芯片的净插入损耗小于1 dB,相位偏差小于±5°。实验测试结果与仿真结果一致。     

大功率量子级联激光器的光学与热学协同优化设计北大核心CSCD

针对大功率量子级联激光器存在热积累严重的问题,本文基于MBE与MOCVD结合的二次外延生长InP基量子级联激光器结构的工艺方法,设计优化中波单管4W连续光输出的大功率量子级联激光器光学与散热性能。通过COMSOL软件对器件结构进行建模,设计器件光学和热学结构模型,分析不同结构参数对器件性能的影响,得到最优结构参数:在In053Ga047As层厚度为50nm,波导下包层InP为1μm,上包层InP为2μm,封装金层厚度为3μm时,器件光学和热学综合性能最优,其中波导光限制因子为074,核心区温度为378 K。本文研究相关结论可为后续大功率中波量子级联激光器结构与工艺设计提供指导。     

基于谐振波导光栅的偏振选择广角光探测器(英文)

高性能偏振选择型光探测器是偏振检测系统中不可或缺的一部分。提出了一种由硅基谐振波导光栅和InP/InGaAs PIN光探测器混合集成的光探测器结构。利用严格耦合波分析方法设计了硅基谐振波导光栅结构,利用时域有限差分法优化了该混合集成光探测器的结构参数。数值仿真结果表明该光探测器在宽带范围内具有高量子效率、较大入射角容差及偏振选择性。该器件可以应用于偏振敏感系统中。     

1967～2033 nm波段硅基可调谐外腔半导体激光器设计与仿真

2μm波长附近可调谐半导体激光器在分子光谱学和光通信领域中有广阔的应用前景。基于绝缘体上硅（SOI）平台,对2μm波长附近可调谐半导体激光器的外腔部分进行了设计优化。分析了不同尺寸光波导的模式损耗特性、单个微环谐振腔受总线波导耦合间距的作用以及总线波导光反馈终端对外腔半导体激光器性能的影响。并提出了一种具有高工艺兼容度的多模环形光波导光反馈结构。所设计的可调谐半导体激光器硅基外腔可通过环形波导上的镍铬合金微加热器进行0.1 nm/K的高精度调谐,对单个微加热器施加3.2 V电压时,调谐范围可达66 nm(1967～2033 nm)。     

基于silica波导光栅的单纤三向器的混合集成研究

通过有源实时监控系统,采用手动和自动相结合的方法,将光纤、silica基阵列波导光栅(AWG)、1310nm激光器(LD)平台和1490nm、1550nm探测器(PD)平台用紫外固化胶混合集成为一新型单纤三向器。在耦合集成过程中,LD在15mA偏置电流下,三向器的上行出纤功率大约为-4dBm,LD和波导的耦合效率大约40%;当三向器输入1550nm光功率为1mW,PD在2.6V反向偏压下,下行输出光电流大约为76μA,波导和PD的耦合效率大约为42%。三向器中采用了对管PD集成方法。     

键合法制备硅基1.55μm InP-InGaAsP量子阱激光器

在硅基上成功地制备出了1.55μm InP-InGaAsP量子阱激光器.设计并生长了适合于键合的量子阱激光器结构材料,通过直接键合技术,将Si衬底与InP-InGaAsP外延片键合到一起.剥离去掉InP衬底后,在5～6μm的薄膜上制备出20μm条形边发射激光器.室温下,阈值电流160mA(电流密度为2.7kA/cm2),功率可达10mW以上(在约350mA电流下),实现了1.55μm长波长边发射激光器与Si的集成.目前,该结果国际上还未见报道.     

键合法制备硅基1.55μm InP-InGaAsP量子阱激光器

在硅基上成功地制备出了1.55μm InP-InGaAsP量子阱激光器.设计并生长了适合于键合的量子阱激光器结构材料,通过直接键合技术,将Si衬底与InP-InGaAsP外延片键合到一起.剥离去掉InP衬底后,在5～6μm的薄膜上制备出20μm条形边发射激光器.室温下,阈值电流160mA(电流密度为2.7kA/cm2),功率可达10mW以上(在约350mA电流下),实现了1.55μm长波长边发射激光器与Si的集成.目前,该结果国际上还未见报道.     

中红外量子级联激光器的光子集成（特邀）

中红外光子集成芯片在环保监测、医疗诊断和国防安全等领域具有广泛的应用前景,但激光光源与无源波导光路的片上集成仍是中红外集成光学需要攻克的关键难题之一。量子级联激光器（QCL）是中红外波段的重要半导体激光光源,文中介绍了近几年中红外QCL在光子集成方面的研究进展,包括InP基单片集成、硅基单片集成、硅基异质键合集成和III-V/锗混合外腔激光器。     

硅基SiO2光波导

在硅基上通过氢氧焰淀积的SiO2,厚度达到了20μm;通过掺Ge增加芯层的折射率,折射率比小于1%,并可调;用反应离子刻蚀工艺对波导的芯层进行刻蚀,刻蚀深度为6μm,刻蚀深宽比大于10;波导传输损耗小于0.6dB/cm(λ=1.55μm),并对波导的损耗机理和测试进行了分析与研究.另外,为实现光纤与波导的耦合,结合微电子机械系统技术,在波导基片上制作了光纤对准V形槽.     

Performance of Hybrid Laser Diodes Consisting of Silicon Slab and InP/InGaAsP Deep‐Ridge Waveguides

The fundamental transverse mode lasing of a hybrid laser diode is a prerequisite for efficient coupling to a single‐mode silicon waveguide, which is necessary for a wavelength‐division multiplexing silicon interconnection. We investigate the lasing mode profile for a hybrid laser diode consisting of silicon slab and InP/InGaAsP deep ridge waveguides. When the thickness of the top silicon is 220 nm, the fundamental transverse mode is lasing in spite of the wide waveguide width of 3.7µm. The threshold current is 40 mA, and the maximum output power is 5 mW under CW current operation. In the case of a thick top silicon layer (1 µm), the higher modes are lasing. There is no significant difference in the thermal resistance of the two devices.     

Hybrid integration of a laser diode and high-silica multimode optical channel waveguide on silicon

An InGaAsP laser diode with 1.34 ?m wavelength and a high-silica multimode optical waveguide were integrated on a common Si substrate using an alignment guide, which is formed simultaneously with the waveguide, for laser diode mounting. The laser-waveguide coupling efficiency was 30%.     

Methods for passive fiber chip coupling of integrated opticaldevices

A useful technique for high precision passive coupling of single mode optical fibers to integrated optical devices is crucial for cost effective packaging especially in multiport devices like switches (N×N) and other WDM components. These devices were fabricated on two different material bases, silicon on insulator (SOI) and polymers. In both cases the waveguides are based on the oversized rib waveguide concept and utilize silicon as a substrate. Two possible fabrication processes for this passive fiber chip coupling IN or ON silicon are presented and compared. The first approach involves a technology similar to flip chip fabrication using a sub- and superstrate, that allows separate processing of v-grooves for fiber alignment and the integrated optical devices. The self aligned mounting of the chip is achieved by a v-shaped rib-groove combination created by wet chemical etching, where the rib is the exact negative of the groove so that the flip chip is put on precisely defined crystal planes rather than on sensitive edges, which would be the case when using rectangular alignment ribs. The second approach utilizes the same chip for waveguides and fiber alignment structures which makes it possible to define both in the same lithographic step and thereby eliminating any vertical displacement. Processing difficulties arise primarily from completely different processing requirements of fiber aligning v-grooves and integrated waveguides. The need to define patterns of the size of only several microns (μm) in the proximity to deep grooves makes the use of an electrophoretic photoresist necessary that is deposited via galvanic means on the extremely nonplanar surface. Both processes allow for fiber chip alignment precisions in the sub-μm range which was also experimentally verified with coupling losses as low as 0.7 dB per end-face. The fabrication processes along with experimental and theoretical results are presented     

GaInAsP/InP integrated laser with butt-jointed built-in distributed-Bragg-reflection waveguide

A novel GaInAsP/InP integrated laser with butt-jointed built-in distributed-Bragg-reflection waveguide (BJB-DBR integrated laser for short) is proposed and demonstrated. In this structure, it is found theoretically that an efficient coupling of 98% between the active and butt-jointed external waveguides is available by matching the propagation constants and the field profiles of both waveguides, which gives relatively larger fabrication tolerance. Prototype BJB-DBR integrated lasers with emitting wavelength of 1.55 ?m were fabricated, and single-longitudinal-mode operation was obtained at room temperature.     

A novel deposit/spin waveguide interconnection (DSWI) for semiconductor integrated optics

We propose an efficient and simple optical interconnection between active semiconductor components by deposition and spin coating. Details of the waveguide design, the fabrication technique, and a promising material combination are given. Experimental results with an integrated laser-polyimide/SiOx(x sim 2) waveguide combination demonstrate low-threshold (2.0 kA/cm²) laser operation and a low-loss waveguide interconnection (81 percent coupling efficiency) on a GaInAsP/InP chip.     

Short-cavity distributed Bragg reflector laser with an integrated tapered output waveguide

A distributed Bragg reflector strained-layer multiple-quantum-well laser at 1.5- mu m wavelength with an integrated tapered waveguide beam expander is discussed. The far-field FWHMs in the lateral and vertical directions are 10 and 15 degrees , respectively. A quantum efficiency of 17% out the tapered facet was measured with a corresponding threshold current of 28 mA. The alignment tolerances for coupling into a cleaved single-mode fiber are 9.5 and 7.5 mu m FWHM in the lateral and vertical directions, respectively. A 3-dB improvement for single-mode fiber coupling using a SELFOC lens was obtained.<>     

Vertical InP/InGaAsP tapers for low-loss optical fibre-waveguide coupling

The authors have realised vertically tapered and antireflection-coated waveguides in InP/InGaAsP with 1.7 dB coupling loss and relaxed alignment tolerances to lensed single-mode fibres with spot diameters of 3.8 mu m. The waveguide tapers are fabricated by a dip-etch process that is well suited for integration with optical waveguide circuits.<>     

A Two-Wafer Approach for Integration of Optical MEMS and Photonics on Silicon Substrate

This letter reports a novel two-wafer approach which demonstrates an integration of optical microelectromechanical system (MEMS) devices and photonics on a silicon substrate. The great advantage of this novel wafer bonding scheme is the ability to maintain the optical axis of the optical MEMS device at the same axis as the optical components. The bonded two wafers which are partially processed, which allows for further processing on the wafer after bonding. Thus, the critical alignment issue is resolved for devices requiring precise alignment in x-/y-/z-axis. Individual functionalities of optical MEMS device and optical coupling between silicon waveguide, fibers and ball lens are demonstrated. This technology shows the potential for integrating silicon photonics integrated circuit and MEMS components with reconfiguration functions on a single silicon substrate.      

芯片式光谱仪光束耦合与对准监测系统设计

针对芯片式光谱仪的光束耦合与对准监测难的问题，提出了一种集成光学系统，避免光纤与芯片式光谱仪接收端接触产生磨损；有效解决光纤遮挡导致无法监测耦合效果的问题。光学系统由耦合前部分系统、监测后部分系统和复合共用系统三部分组成，复合共用系统需同时配合耦合前部分系统与监测后部分系统分别完成光束耦合与对准监测的功能。采用多重组合方式对整体系统进行设计，针对6 μm入射光纤与20 μm×20 μm的芯片式光谱仪接收端，在（1 550±50） nm的工作谱段对光纤光束与芯片式光谱仪接收端耦合系统与监测系统进行了设计，并通过LightTools软件对耦合系统进行能量分析，计算耦合效率为0.733。整体系统结构简单且无需手动调节，可同时进行光束耦合与对准监测，为芯片式光谱仪的耦合及监测提供了一种新方法。     

Beyond G-band: a 235 GHz InP MMIC amplifier

We present results on an InP monolithic millimeter-wave integrated circuit (MMIC) amplifier having 10-dB gain at 235GHz. We designed this circuit and fabricated the chip in Northrop Grumman Space Technology's (NGST) 0.07-/spl mu/m InP high electron mobility transistor (HEMT) process. Using a WR3 (220-325GHz) waveguide vector network analyzer system interfaced to waveguide wafer probes, we measured this chip on-wafer for S-parameters. To our knowledge, this is the first time a WR3 waveguide on-wafer measurement system has been used to measure gain in a MMIC amplifier above 230GHz.