Silicon on sapphire CMOS for optoelectronic microsystems

we report on a hybrid integration approach that represents a paradigm shift from traditional optoelectronic integration and packaging methods. A recent metamorphosis and wider availability of silicon on sapphire CMOS VLSI technology is generating a great deal of excitement in the optoelectronic systems community as it offers simple and elegant solutions to the many system integration and packaging challenges that one faces when employing bulk silicon CMOS technologies. In the bulk silicon CMOS processes that are used for high-speed interface electronics the substrate is absorbing at both 850 nm and 980 nm wavelengths, necessitating complex and expensive integration procedures such as VCSEL substrate removal to enable the implementation of optical vias through the substrate. Working together, the optical transparency of the sapphire substrate, its superb thermal conductivity and the excellent high speed device characteristics of silicon-on-sapphire CMOS circuits make this technology an excellent choice for cost effective optoelectronic Die-AS-Package (DASP) systems and for implementing optical interconnects for high performance computer architectures. What is perhaps even more important, packaging and input/output interface issues can now be addressed at the CMOS wafer fabrication level where input/output structures can be accurately defined, optimized and processed using lithographic techniques, eliminating problematic die post-processing and packaging-related optical alignment issues     

面向中红外应用的硅基光电子学最近研究进展

随着信息传递、处理以及存储能力要求的不断提升,传统的近红外通信波段已呈“容量紧缩”之势。而工艺与CMOS兼容、结构简单、成本低廉的硅基光电子技术在中红外信号传输和处理方面已经显示出独特优势,有望在中红外波段实现大规模集成,在非线性光学等领域实现新的飞跃。首先介绍了硅基光电子技术在中红外应用中的优势以及目前研究过程中所遇到的困难和挑战;其次结合材料属性和结构特性对一些基本元件（如波导、分束/合束器、二极管）等在中红外领域的最新研究成果进行了介绍;最后对近5年来在中红外波段所实现传感应用的非线性光学硅基器件（基于FWM的非线性光学器件、频率梳）和面向中红外通信应用的激光器、调制器、光电探测器进行了成果介绍,并对研究进展进行了总结。     

Gallium arsenide joins the giants

Gallium arsenide has enjoyed a unique position in the electronics industry for more than 25 years. GaAs is emerging as the starting material for integrated circuits with one million or more transistors per chip. The technology today is firmly in the domain of high-performance, very large-scale integration (VLSI), with chip clock rates hitting 100 MHz and up, whilst maintaining a reasonable manufacturing cost. Here, the author describes how present forms of GaAs VLSI are higher-performing versions of silicon VLSI. The GaAs transistors just speed up the same old IC concepts. Still in the future are truly novel chips, incorporating devices like optical emitters or microwave amplifiers that can be built only in GaAs III-V compounds     

硅基单片集成单边带调制器

基于CMOS兼容的硅基光子集成工艺,设计并实现了一种具有高边带抑制比的硅基单片集成单边带调制器。单边带调制器采用正交混合耦合器实现上下两臂等幅度、90°相位差的射频信号加载,基于硅基双驱动马赫曾德尔调制器的热移相器调控上下两臂光相位差为90°,实现了效果显著的单边带抑制。基于CUMEC公司CSiP180 Al工艺和工艺设计包(PDK)完成芯片制备,采用金丝引线实现了正交混合耦合器的空气桥结构。测试结果显示该硅基单片集成单边带调制器在18~32 GHz频率内边带抑制比均高于12 dB,在21 GHz工作频率时边带抑制比达到了32 dB。该单边带调制器有望应用在光通信和微波光子系统中。     

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.      

Silicon Nanocrystals as an Enabling Material for Silicon Photonics

Silicon nanocrystals (Si-nc) is an enabling material for silicon photonics, which is no longer an emerging field of research but an available technology with the first commercial products available on the market. In this paper, properties and applications of Si-nc in silicon photonics are reviewed. After a brief history of silicon photonics, the limitations of silicon as a light emitter are discussed and the strategies to overcome them are briefly treated, with particular attention to the recent achievements. Emphasis is given to the visible optical gain properties of Si-nc and to its sensitization effect on Er ions to achieve infrared light amplification. The state of the art of Si-nc applied in a few photonic components is reviewed and discussed. The possibility to exploit Si-nc for solar cells is also presented. In addition, nonlinear optical effects, which enable fast all-optical switches, are described.     

Silicon Photonics: CMOS Going Optical

For almost 50 years, silicon microelectronics has been the engine of the modern information revolution. Complex microprocessors, dense memory circuits, and other digital and analog electronics produced by the $100 billion silicon industry mainly serve a single goal - to process more and more data faster and faster using smaller and smaller components. In this everlasting quest, the silicon industry has successfully overcome many critical issues that were initially considered to be impassible road blocks. Recent progress in silicon compatible photonics is driving high density integration of photonic and electronic components manufactured by CMOS-based technology on the same platform.This Special Issue presents a set of review papers addressing major challenges and summarizing recent progress in the several subfields of Si-based photonics.     

Photonics-to-electronics integration for optical interconnects in the early 21st century

It is useful to examinethe history of penetration opti-cal datalinksinto communication over thelast 30 years .Fig.1 shows an approxi mate perspective of the rate ofpenetration of optics versus the link distance and thebandwidth.Thelower horizontal axis re…     

Future prospects of silicon photonics in next generation communication and computing systems

The recent progress is reviewed and future prospects of silicon photonics in next generation communication and computing systems are probed. Leveraging the many-billion-dollar complementary metal-oxide-semiconductor (CMOS) industry, silicon photonics has promising prospects for realising very large-scale electronic and photonic integrated circuits with thousands of optical components and millions of transistors in the future to support very demanding integrated systems needs of next generation computing and communications. There are also a number of significant challenges in fulfilling such prospects.     

High-speed, compact silicon and hybrid plasmonic waveguides for signal processing

All-optical circuits for signal processing could be a promising solution to overcome the speed bottleneck of electronics.For the photonics industry,silicon becomes a competitive material of choice in the field of integrated optics for designing and implementing high-speed and compact photonic devices.To further increase the integration density,it is a critical challenge to manipulate light on scales much smaller than the wavelength for the dielectric waveguides due to the diffi-action limitation.Surface plasmon-polaritons (SPPs),which break the diffraction limitation,are receiving increasing attentions in recent years.This paper compares the advantages and disadvantages between electronic devices and optical devices taking differentiator as an example,and proposes an optical parametric amplifier (OPA) using silicon-based hybrid plasmonic waveguide.     

Photoic crystal nanobeam cavity devices for on-chip integrated silicon photonics

Integrated circuit(IC)industry has fully considered the fact that the Moore’s Law is slowing down or ending.Alternative solutions are highly and urgently desired to break the physical size limits in the More-than-Moore era.Integrated silicon photonics technology exhibits distinguished potential to achieve faster operation speed,less power dissipation,and lower cost in IC industry,because their COMS compatibility,fast response,and high monolithic integration capability.Particularly,compared with other on-chip resonators(e.g.microrings,2D photonic crystal cavities)silicon-on-insulator(SOI)-based photonic crystal nanobeam cavity(PCNC)has emerged as a promising platform for on-chip integration,due to their attractive properties of ultra-high Q/V,ultra-compact footprints and convenient integration with silicon bus-waveguides.In this paper,we present a comprehensive review on recent progress of on-chip PCNC devices for lasing,modulation,switching/filting and label-free sensing,etc.     

Recent Progress on Metal-Based Nanomaterials: Fabrications,Optical Properties,and Applications in Ultrafast Photonics

Nanomaterials have demonstrated excellent mechanical, thermal, optical, and electrical properties in various fields, including 1D carbon nanotubes, as well as 2D materials starting from graphene. Metal-based nanomaterials, mainly divided into metal and metal oxide nanoparticles, also gradually come into the sight of ultrafast photonics applications due to the outstanding optical properties. The optical properties of metal nanoparticles can be enhanced by the interaction between conduction electrons with electric fields that is called surface plasmon resonance. As for metal oxide nanoparticles, optical properties are closely related to bandgap structures. When it comes to transition metal oxides, other phenomena also play important roles in optical absorption such as spin inversion and excitons of iron. Moreover, preparation methods of materials are also crucial for their properties and further applications. Therefore, in this review, commonly used physical and chemical fabrication methods for metal-based nanomaterials are first introduced. Then the optical properties of typical metal and metal oxide nanoparticles are discussed specifically. In addition, the applications of metal-based nanomaterials in ultrafast lasers based on mode-locked and Q-switched techniques are also summarized. Finally, a summary and outlook toward the synthesis, optical properties, and applications in ultrafast photonics of metal-based nanomaterials are presented.     

硅光子器件及其集成技术的研究

主要探讨了偏振分集光路、可调光衰减器、波导耦合型锗光电探测器等硅光器件的研究进展,分析了其结构及技术参数,随后探讨了VOA-PD单片集成技术以及VMUX单片集成技术两种硅基单片集成技术,指出硅光子器件的性能指标已经能满足现代光纤通信系统的要求。     

从GFP2011看硅光子学的进展

半导体硅材料不仅是一种电子材料,也是一种合适的光子材料。成熟的微电子加工工艺更为硅光子学提供了坚实的技术基础。根据第八届Ⅳ族光子学国际会议的信息,文章综述了硅基光波导技术特别是SOI光波导技术研究的最新进展,着重介绍了光调制器、亚波长光栅、混合集成、封装以及波导加工等方面的新理念与新方法。     

Silicon photonics: the optical spice rack

Silicon is evolving as a versatile photonics platform with multiple functionalities that can be seamlessly integrated. The toolbox is rich, starting from the ability to guide and switch multiple wavelength sources at gigahertz bandwidths, to optomechanical MEMS and opto-fluidics devices. Some of the challenges in the field of silicon photonics are discussed; among them are the decrease of losses in silicon waveguides and the integration of silicon photonics with current CMOS microelectronics.     

光子学在材料工业中的应用

评述光子学在材料工业的光学硅、纳米材料、光子晶体和集成光路中的应用。     

Thermal effect analysis of silicon microring optical switch for on-chip interconnect

The silicon microring resonator plays an important role in large-scale, high-integrability modern switching matrixes and optical networks, as silicon photonics enables ring resonators of an unprecedented compact size. But as the nature of resonators is their sensitivity to temperature, their performances are vulnerable to being affected by thermal effect. In this paper, we analyze the dominant thermal effects to the application of silicon microring optical switch. On the one hand we theoretically analyze and experimentally measure the thermal crosstalk among adjacent microring optical switches with different distances, and give possible solutions to minimize the affect of thermal crosstalk. On the other hand we analyze and measure the thermooptic dynamic response of microring switch; the experiment shows for the thermal-tuning that the rising edge is around 2μs, and the falling edge is around 35μs. We give the explanation of the asymmetric rise-time and fall-time.     

Monolithic integration of waveguide polymer electrooptic modulators on VLSI circuitry

We demonstrated some of the critical technology that is needed for the monolithic integration of polymer electrooptic modulators and VLSI circuitry by fabricating and testing a phase slab modulator on nonplanar VLSI circuits. We demonstrated the survival of GaAs MESFET's to the high-voltage poling and polymer modulator fabrication procedures. We also implemented an electrical interconnect scheme between the electronics and photonics layers.     

Effective Silicon Oxide Formation on Silica‐on‐Silicon Platforms for Optical Hybrid Integration

This paper describes an effective method for forming silicon oxide on silica‐on‐silicon platforms, which results in excellent characteristics for hybrid integration. Among the many processes involved in fabricating silica‐on‐silicon platforms with planar lightwave circuits (PLCs), the process for forming silicon oxide on an etched silicon substrate is very important for obtaining transparent silica film because it determines the compatibility at the interface between the silicon and the silica film. To investigate the effects of the formation process of the silicon oxide on the characteristics of the silica PLC platform, we compared two silicon oxide formation processes: thermal oxidation and plasma‐enhanced chemical vapor deposition (PECVD). Thermal oxidation in fabricating silica platforms generates defects and a cristobalite crystal phase, which results in deterioration of the optical waveguide characteristics. On the other hand, a silica platform with the silicon oxide layer deposited by PECVD has a transparent planar optical waveguide because the crystal growth of the silica has been suppressed. We confirm that the PECVD method is an effective process for silicon oxide formation for a silica platform with excellent characteristics.     

2D Tellurium Based High‐Performance All‐Optical Nonlinear Photonic Devices

Tellurium (Te), as one of the rarest stable solid elements far more common in the universe than on earth, is a p‐type semiconductor with excellent optical properties. Herein, a novel two‐dimensional (2D) Te nanosheets (Ns)‐based air‐stable nonlinear photonic devices: all‐optical switcher and photonic diode, owing to its strong light–matter interaction in the visible‐to‐infrared band are reported. The findings validate that the proposed photonic diode can be utilized for the function of nonreciprocal light propagation in optical telecommunications or integrated photonics. Moreover, 2D Te‐based light‐modulate‐light system is successfully designed to realize “ON” and “OFF” modes for all‐optical switching operation. This work highlights a good promise of 2D Te in the field of nonlinear photonics, leading to an important step toward 2D Te‐based advanced photonics devices. The versatile solution process allows a universal access of 2D Te as a new 2D material in a wider range of photonics device applications such as, detector, modulator, switcher, etc.