基于光二分路器的多路分光比的设计

提出一种设计多路分光器分光比的新方法--分解组合法.将多路分光器视为光二分路器的各种组合,分解后,引入等效光纤长度的新概念,将分光损耗对等折算为一定长度的光纤损耗,再利用光二分路器分光比的简便设计方法,巧妙地设计出多路分光器的各路分光比.     

Optical Clock Distribution in Electronic Systems

Techniques for distribution of optical signals, both free space and guided, within electronic systems has been extensively investigated over more than a decade. Particularly at the lower levels of packaging (intra-chip and chip-to-chip), miniaturized optical elements including diffractive optics and micro-refractive optics have received considerable attention. In the case of optical distribution of data, there is the need for a source of optical power and a need for a means of modulating the optical beam to achieve data communications. As the number of optical data interconnections increases, the technical challenges of providing an efficient realization of the optical data interconnections also increases. Among the system signals which might be transmitted optically, clock distribution represents a substantially simplified problem from the perspective of the optical sources required. In particular, a single optical source, modulated to provide the clock signal, replaces the multitude of optical sources/modulators which would be needed for extensive optical data interconnections. Using this single optical clock source, the technical problem reduces largely to splitting of the optical clock beam into a multiplicity of optical clock beams and distribution of the individual clocks to the several portions of the system requiring synchronized clocks. The distribution problem allows exploitation of a wide variety of passive, miniaturized optical elements (with diffractive optics playing a substantial role). This article reviews many of the approaches which have been explored for optical clock distribution, ranging from optical clock distribution within lower levels of the system packaging hierarchy through optical clock distribution among separate boards of a complex system. Although optical clock distribution has not yet seen significant practical application, it is evident that the technical foundation for such clock distribution is well established. As clock rates increase to 1 GHz and higher, the practical advantages of optical clock distribution will also increase, limited primarily by the cost of the optical components used and the manufacturability of an overall electronic system in which optical clock distribution has been selectively inserted.     

硅光学双稳态(SOB)器件

利用作者近期研制的硅光电表面负阻晶体管（PNEGIT）或光电“∧”双极晶体管（PLBT）两种硅光电负阻器件,提出并成功地实现了一种新型的硅光学双稳态器件。即以PNEGIT（或PLBT）作为光的输入器件,以其驱动一发光管（LED）作为光输出器件,由于PNEGIT和PLBT都具有光电负阻特性,致使在输出光功率（Pout）-输入光功率（Pin）特性上出现逆时针方向的光学双稳回线。这种器件具有光开关、光逻辑、光放大、光存贮、光眼福等多种功能,扩展了硅光电器件在光逻辑、光计算、光通讯等领域中的应用。     

Mechanically Flexible Chip-to-Substrate Optical Interconnections Using Optical Pillars

We experimentally characterize the benefits of using surface-normal mechanically flexible optical waveguides, or optical pillars, for chip-to-substrate optical interconnection. In order to benchmark the performance of the optical pillars, the optical coupling efficiency from a light source to an optical aperture with and without an optical pillar is measured. For a light source with 12deg beam divergence, a 50times150 mum optical pillar improves the coupling efficiency by 2-4 dB compared to pillar-free (free-space) optical coupling. A 30times150 m optical pillar improves the coupling efficiency by 3-4.5 dB. This demonstrates the importance of using optical pillars when small photodetectors (PDs) and dense optical input/outputs (I/Os) are needed. The optical excess losses of 50times150 mum optical pillars are measured to be less than 0.2 dB. Due to the high mechanical flexibility of the pillars, we also demonstrate that optical pillars enhance the optical coupling efficiency between the chip and substrate when they are misaligned in the lateral direction. This is especially important since the coefficient of thermal expansion of the chip and substrate are often mismatched, and preserving optical alignment and interconnection between them is critical during thermal excursions. The lateral mechanical compliance of the optical pillars is also measured and can be as great as 30 mum/mN. The optical pillars are also shown to be compliant under a compressive force thus allowing the optical I/Os to be assembled on nonplanar surfaces such as low-cost organic substrates.     

采用角度分集接收技术的光学天线设计

为了克服可见光通信系统中码间干扰的影响,利用角度分集接收技术,提出了在半球体上分布多个朝向不同的光锥作为光学接收天线新方法。应用Zemax光学设计软件,结合Matlab工具和Origin软件的数据处理分析,通过仿真单个光锥在不同半顶角取值时小端面上的光强值随光线入射角的变化量,拟合得到了相应的函数表达式和曲线图;并在光锥集光器分布夹角的数值分析基础上,根据同一个光信号在相邻两个光锥小端面上的光强关系,确定了光锥两两之间的夹角,给出了具体的布局设计方案;最后讨论了整个半球系统上总光强的接收情况。     

Nonlinear optics in fibers for fiber measurements and special device functions

Nonlinear optical effects in fibers are significant in three respects. They present undesirable transmission limitations for long-distance optical fiber communication systems due to the intensity-dependent loss and pulse waveform distortions. On the useful side, they provide efficient frequency conversion means for generating frequency-shifted optical sources for a variety of spectroscopic applications including optical fiber measurements and optical device characterization. In addition, nonlinear optical effects also can provide useful special optical device functions such as optical amplification, optical gating, optical pulseshaping, and waveform equalization. This paper gives a brief review of the latter two aspects of nonlinear optics in fibers.     

Optical clock-pulse-train generator for processing preamble-free asynchronous optical packets

An optical clock-pulse-train generator (OCPTG) for processing asynchronous arbitrary-length optical packets with no preamble is developed. The OCPTG consists of a fiber-loop-based optical pulse-train generator (PTG) and an optical clock-pulse generator that, for every input asynchronous optical packet, generates a single, synchronized optical pulse which is fed to the PTG. Generation of an optical clock-pulse-train with stable pulse energy, precise repetition rate, and duration matching the input packet is achieved for variable-length optical packets. The OCPTG and an all-optical demultiplexer combined demonstrate error-free demultiplexing of a 10-Gb/s asynchronous optical packet stream.     

高集成度四视场中波红外光学系统

为了实现超小型化、长焦距和超大视场,提出并设计了一种高集成度四视场中波红外光学系统。该系统采用双光路结构形式,包括超小视场光路和小/中/大视场光路,两支光路共用中继组;对超小视场光路进行了四次立体折叠,并对小/中/大视场光路进行了二次折叠。通过以上六次折叠,整个双光路光学系统的外形尺寸得到了有效约束,其外形包络在242 mm×150 mm×85 mm (局部125 mm)范围内,系统集成度高。这种双光路光学系统包括超小视场、小视场、中视场和大视场四个视场。其中,超小视场的焦距为688 mm,视场为0.8°;大视场的焦距为13.19 mm,视场为40°,实现了长焦距和超大视场并存,并获得了50×的变倍比;超小视场光学系统仅采用5片透镜,透过率高,并具有光学被动消热差设计;整个双光路光学系统结构紧凑,体积小,实现了超小型化。设计结果表明,该光学系统像质良好,可以满足高性能热像仪的使用要求。     

Chip-to-Chip Optical Link System Using an Optical Wiring Method

A practical optical link system was prepared with a transmitter (Tx) and receiver (Rx). The optical TRx module consisted of a metal optical bench, a module printed circuit board, a driver/receiver integrated circuit, a vertical-cavity surface-emitting laser/photodiode array, and an optical link block composed of plastic optical fiber (POF). For the optical interconnection between the light-sources and detectors, an optical wiring method has been proposed to enable easy assembly. The optical wiring link was constructed with POFs mounted on a v-grooved polymethylmethacrylate bench. The data transfer measurements were presented successfully.     

空间光学遥感器的光学元件组件的频率设计

空间光学遥感器的光学元件的光学参数通常是根据设计经验来选定的.建立了空间光学遥感器的全阻尼动态分析模型,得到了光学元件动态响应的表达式.从工程的实际条件出发,当阻尼比为0.03、质量比为0.2时,通过MATLAB编程对光学元件的动态响应进行了数值分析.结果表明,为了尽可能地降低光学元件的动态响应,应该选择合理的动态频率,而不是一味地提高光学元件组件的动态频率.     

Efficient reversible NOR gates and their mapping in optical computing domain

Reversible logic is a computing paradigm in which there is a one to one mapping between the input and the output vectors. Reversible logic gates are implemented in an optical domain as it provides high speed and low energy computations. In the existing literature there are two types of optical mapping of reversible logic gates: (i) based on a semiconductor optical amplifier (SOA) using a Mach–Zehnder interferometer (MZI) switch; (ii) based on linear optical quantum computation (LOQC) using linear optical quantum logic gates. In reversible computing, the NAND logic based reversible gates and design methodologies based on them are widely popular. The NOR logic based reversible gates and design methodologies based on them are still unexplored. In this work, we propose two NOR logic based n-input and n-output reversible gates one of which can be efficiently mapped in optical computing using the Mach–Zehnder interferometer (MZI) while the other one can be mapped efficiently in optical computing using the linear optical quantum gates. The proposed reversible NOR gates work as a corresponding NOR counterpart of NAND logic based Toffoli gates. The proposed optical reversible NOR logic gates can implement the reversible boolean logic functions with a reduced number of linear optical quantum logic gates or reduced optical cost and propagation delay compared to their implementation using existing optical reversible NAND gates. It is illustrated that an optical reversible gate library having both optical Toffoli gate and the proposed optical reversible NOR gate is superior compared to the library containing only the optical Toffoli gate: (i) in terms of number of linear optical quantum gates when implemented using linear optical quantum computing (LOQC), (ii) in terms of optical cost and delay when implemented using the Mach–Zehnder interferometer.     

High Extinction Ratio Mach–Zehnder Modulator Applied to a Highly Stable Optical Signal Generator

Research into optical modulators has made remarkable progress in recent years. This paper discusses the possibility of applying the high extinction ratio optical modulator to a high-stability and high-frequency (over 100 GHz) optical reference signal generator. High-frequency reference signals are generated by a highly stable optical two-tone generator, which is used for high-rate communication and astronomical application. One method to generate two optical signals is producing them from a pair of laser sources using an optical phase-locked loop for feed back control; however, the optical phase-locked loop has a stability problem in its operation. A good alternative method to the optical phase-locked scheme is the LiNbO³ Mach-Zehnder (MZ) optical intensity modulator, which is capable of generating two highly stable optical signals (upper sideband and lower sideband components) by applying a sinusoidal microwave signal to an input laser signal. The two optical signals require phase stability better than 10^-13 in the Allan standard deviation, vibration robustness, and polarization maintaining capability. The signal coherence loss estimated from the phase stability of the two optical signals generated by the MZ modulator shows that the optical MZ modulator has the ability to generate highly stable optical signals.     

Chip-scale optical interconnects and optical data processing using silicon photonic devices

Recent advances in the density and complexity of photonic integrated circuits have facilitated possible implementation of chip-scale optical communication systems. Chip-scale optical interconnects and optical data processing are two important functions to transmit and process signal in the optical domain. Silicon photonics offers a promising platform to enable chip-scale optical interconnects and optical data processing using silicon photonic devices. In this paper, we review our recent progress in the design, modeling, and fabrication of silicon photonic devices and their applications in chip-scale optical interconnects and optical data processing with advanced modulation formats. For chip-scale optical interconnects, we experimentally demonstrate digital signal transmissions in silicon microring and silicon vertical slot waveguide. Terabit chip-scale optical interconnect is demonstrated in the experiment. Also, we experimentally demonstrate analog signal transmissions in silicon microring and silicon photonic crystal nanocavity. For chip-scale optical data processing, we experimentally demonstrate all-optical wavelength conversion using a silicon waveguide, simultaneous polarization and wavelength demultiplexing using 2D grating coupler connected with microrings, two-mode (de)multiplexing using a tapered asymmetrical grating-assisted contra-directional coupler, and two-/three-mode (de)multiplexing using asymmetrical directional converter. In addition, we propose and simulate chip-scale optical data exchange, chip-scale high-base optical computing, and chip-scale optical coding/decoding by using nonlinear interactions in a silicon-organic hybrid slot waveguide. The obtained theoretical and experimental results of chip-scale optical interconnects and optical data processing indicate possible integration of optical communication functions on a monolithic chip.     

光纤CATV传输系统的结构和应用

光纤CATV传输系统包括光发射机、光接收机、光纤和必要的光通路器件（如光分路器、光纤连接器）等。该系统采用光纤／同轴电缆混合网（HFC）结构，是一种宽带、低成本的实现方式。结合实际开发工作，简要介绍了光发射机、光接收机及相关器件的工作原理。     

光通信网新技术

新技术的开发和使用使得光网络层具有了许多原先只能在高层实现的网络功能,并使原先单纯为了增加传输容量的ＷＤＭ层具有了真正的光联网功能。以光标记交换技术、交突发分组交换技术、无纤光通信系统以及全新的光互联网技术为代表构成了今天的光通信网研究热点并了世界各国科研院所和著名通信公司的广泛关注。     

光网络性能监测技术

光网络性能监测(OPM)已成为下一代光网络发展的关键技术,构建满足光网络发展需求的OPM系统也已成为物理层技术的发展重点。本文在介绍光网络性能监测主要内容、关键技术、光采样技术的基础上,总结了目前光网络发展对光性能监测技术的主要要求,同时分析了目前应用的部分技术难点和后续发展趋势。     

All-optical signal processing based on semiconductor optical amplifiers

In this paper,we review the recent progress in the optical signal processing based on the nonlinearity of semiconductor optical amplifiers (SOAs).The four important optical signal processing functional blocks in optical switching are presented,i.e.,optical wavelength conversion,optical regeneration,optical logic,and optical format conversion.We present a brief overview of optical wavelength conversion,and focus on various schemes to suppress the slow gain recovery of the SOA and improve the operating speed of the SOA-based optical switches.Optical regeneration including re-amplification,re-shaping and re-timing is also presented.Optical clock recovery that is essential for optical regeneration is reviewed.We also report the recent advances in optical logic and optical format conversion,respectively.After reviewing the four important optical signal processing functional blocks,the review concludes with the future research directions and photonic integration.     

Optical functional device by vertical and direct integration ofheterojunction phototransistor and laser diode

An optical device with various functions is actualized by integrating vertically and directly heterojunction phototransistors and a laser diode and by adjusting the internal optical feedback. The optical amplification with a good linearity between input and output lights is realized by suppressing the internal optical feedback. The large gain of over 100 is achieved in the wide wavelength range from 0.75 to 1.25 μm. The optical thresholding function is achieved by changing the load line in the case of the optical amplification. The optical switching function with large gain and high sensitivity is obtained by utilizing the internal optical feedback most effectively. The optical bistable function is obtained when the amount of the optical feedback becomes moderate. The optical feedback inside the device is theoretically investigated to explain these functions systematically     

Optical packet switching and buffering by using all-optical signal processing methods

We present a 1 /spl times/ 2 all-optical packet switch. All the processing of the header information is carried out in the optical domain. The optical headers are recognized by employing the two-pulse correlation principle in a semiconductor laser amplifier in loop optical mirror (SLALOM) configuration. The processed header information is stored in an optical flip-flop memory that is based on a symmetric configuration of two coupled lasers. The optical flip-flop memory drives a wavelength routing switch that is based on cross-gain modulation in a semiconductor optical amplifier. We also present an alternative optical packet routing concept that can be used for all-optical buffering of data packets. In this case, an optical threshold function that is based on a asymmetric configuration of two coupled lasers is used to drive a wavelength routing switch. Experimental results are presented for both the 1 /spl times/ 2 optical packet switch and the optical buffer switch.     

基于超高Q值氟化镁晶体微腔的克尔光频梳产生研究

克尔光频梳具有等距分布的梳状光谱结构,在精密测量、光钟、相干光通信、微波和光学任意波产生、光谱学及天文光谱仪校准等方面有着重要的应用。首先,微腔光频梳与其他光频梳系统相比,具有集成性高、体积小、功耗低的优势,大大扩展了光频梳的应用;其次,通过超精密加工方法制备了品质因子Q值达到了4.8×107的氟化镁微腔,并且得到了干净规律、排列规则的谐振谱,自由频率范围为9.73 GHz,为产生低重复频率光频梳提供了条件;最后,根据实验结果结合Lugiato-Lefever方程分析了氟化镁微腔光频梳的产生过程,研究了泵浦功率对光频梳的影响,通过调整失谐参数得到了孤子态光频梳。并且通过色散调控优化了微腔的光场模式,为产生具有超光滑光谱的孤子光频梳创造了先决条件,提升了光频梳性能。