共查询到20条相似文献,搜索用时 31 毫秒
1.
Huei Pei Kuo Paul Rosenberg Robert Walmsley Sagi Mathai Lennie Kiyama Joseph Straznicky Moray Mclaren Michael Tan Shih-Yuan Wang 《Applied Physics A: Materials Science & Processing》2009,95(4):955-965
We describe two free-space optical links for multichannel optical interconnects. The targeted aggregate data rate is 240 Gb/s.
In one implementation we use a unique implementation of telecentric optics and achieved an optical link that is simple, robust,
and modular. We describe a simple, inexpensive telecentric lens that can accommodate all optical channels within a 1-mm-diameter
sweet zone. We also describe the performance of an optical link with a 4×4 array of VCSELs and matching detectors. The integrity
of the optical link is not significantly degraded with a>±2 mm translational misalignment between the VCSEL and detector arrays. With the telecentric optical link, we need only two
low-bandwidth, single-axis active servomechanisms to compensate for static tilt and possibly low-frequency thermally-driven
shift between the transmitter and receiver arrays. In the other implementaion we use two matching arrays of 1×12 optical fibers.
Data are coupled optically through an air gap of 2 mm by means of a pair of collimating microlens arrays that are aligned
to one another via precision mechanical subassemblies. We describe a simple, inexpensive, and robust mechanical coupling for
the optical link achieved by using miniature high-flux magnets. 相似文献
2.
无衍射光的中心光斑直径相对于高斯光束较小且发散角为零,在自由空间光通信领域具有良好的应用前景。介绍了一种自由空间无衍射光通信模拟实验系统,它通过串口连接上位机,应用微处理器进行信号的调制与解调,采用双头脉冲间隔调制,无衍射光的发生使用圆锥透镜法,在接收端使用PIN光电二极管将光信号转换为电信号,再经过放大电路、整形电路和微处理器的解调,最后通过串口将数据传输给上位机。上位机通过对发送数据与接收数据的对比计算出误码率,进而给出整个系统的传输性能评价。在无衍射光的最大传输距离内,当比特率为9 600 bps时,该系统的误码率优于610-5。 相似文献
3.
We present a quantum-correlation-based free-space optical(FSO) link over 250 m using an outdoor active reflector 125 m from the transceiver station. The performance of free-space optical communication can be significantly degraded by atmospheric turbulence effects, such as beam wander and signal fluctuations. We used a 660 nm tracking laser to reduce atmospheric effects, by analyzing the fast beam wander and slow temporal beam drift, using this information to correct the quantum channel alignment of the 810 nm signal photons. In this work, the active reflector consisted of a mirror, a 6-axis hexapod stage, and a long-range wireless bridge. The slow drift of the beam path due to outdoor temperature changes was steered and controlled using wireless optical feedback between the receiver units and the active reflector. Our work provides useful knowledge for improved control of beam paths in outdoor conditions, which can be developed to ensure high quality quantum information transfer in real-world scenarios, such as an unmanned FSO link for urban quantum communication or retro-reflective quantum communication links. 相似文献
4.
光学涡旋的产生、传输与应用是当前光学领域的研究热点之一.光学涡旋具有轨道角动量,作为一种全新的自由度,丰富了目前光通信的方式.利用面向目标的共轭对称延拓傅里叶计算全息技术,基于空间光调制器,用单束激光直接产生混合光模式阵列进行编码通信.采用由单光涡和复合光涡构成的4种易于识别的模式组成2×2混合光模式阵列,进行灰度图像的编码传输.在接收端提取混合光模式阵列图的信息并进行解码,实现零误码的灰度图像再现.以传输一幅Lena图像为例,使用2×2混合光模式阵列进行编码通信,相对于传统单光涡编码通信,其信息容量可增加4倍.该方法光路简单易行,可扩展性强,进一步拓展使用4×4混合光模式阵列进行编码通信,信息容量提升16倍.提出的混合光模式阵列编码通信方法对于提高信息传输容量具有重要价值. 相似文献
5.
Narasimha S. Prasad 《Journal of Optical and Fiber Communications Reports》2005,2(6):558-602
The mid-wave IR (MWIR) spectral band extending from 3 to 5 microns is considered to be a low loss atmospheric window. The
MWIR wavelengths are eye safe and are attractive for several free-space applications including remote sensing of chemical
and biological species, hard target imaging, range finding, target illumination, and free-space communications. Due to the
nature of light-matter interaction characteristics, MWIR wavelength based systems can provide unique advantages over other
spectral bands for these applications. The MWIR wavelengths are found to effectively penetrate natural and anthropogenic
obscurants. Consequently, MWIR systems offer increased range performance at reduced power levels. Free-space, line-of-sight
optical communication links for terrestrial as well as space based platforms using MWIR wavelengths can be designed to operate
under low visibility conditions. Combined with high-bandwidth, eye-safe, covert and jam proof features, a MWIR wavelength
based optical communication link could play a vital role in hostile environments.
A free-space optical communication link basically consists of a transmitter, a receiver and a scheme for directing the beam
towards a target. Coherent radiation in the MWIR spectral band can be generated using various types of lasers and nonlinear
optical devices. Traditional modulation techniques are applicable to these optical sources. Novel detector and other subcomponent
technologies with enhanced characteristics for a MWIR based system are advancing. Depending on the transmitter beam characteristics,
atmospheric conditions may adversely influence the beam propagation and thereby increasing the bit error rate. For satisfactory
transmission over a given range, the influence of atmosphere on beam propagation has to be analyzed. In this chapter, salient
features of atmospheric modeling required for wavelength selection and performance prediction is presented. Potential optical
sources and detectors for building a practical MWIR communication link are surveyed. As an illustration, the design configuration
and experimental results of a recently demonstrated free-space, obscurant penetrating optical data communication link suitable
for battlefield applications is discussed. In this case, the MWIR wavelength was derived using an all solid-state, compact,
optical parametric oscillator device. With this device, weapon codes pertaining to small and large weapon platforms were
transmitted over a range of 5 km. Furthermore, image transmission through light fog, accomplished using this hardware, is
also presented.
Advances in source and detector technologies are contributing to the development of cost effective systems compatible with
various platforms requirements. In coming years, MWIR wavelengths are anticipated to play a vital role in various human endeavors. 相似文献
6.
Jeffrey Chou Kyoungsik Yu David Horsley Brian Yoxall Sagi Mathai Michael R. T. Tan Shih-Yuan Wang Ming C. Wu 《Applied Physics A: Materials Science & Processing》2009,95(4):973-982
We present a free-space optical interconnect system capable of dynamic closed-loop optical alignment using a microlens scanner
with a proportional integral and derivative controller. Electrostatic microlens scanners based on combdrive actuators are
designed and characterized with vertical cavity surface emitting lasers (VCSELs) for adaptive optical beam tracking in the
midst of mechanical vibration noise. The microlens scanners are fabricated on silicon-on-insulator wafers with a bulk micromachining
process using deep reactive ion etching. We demonstrate dynamic optical beam positioning with a 700 Hz bandwidth and a maximum
noise reduction of approximately 40 dB. Eye diagrams with a 1 Gb/s modulation rate are presented to demonstrate the improved
optical link in the presence of mechanical noise. 相似文献
7.
J. Beals N. Bamiedakis A. Wonfor R. V. Penty I. H. White J. V. DeGroot K. Hueston T. V. Clapp M. Glick 《Applied Physics A: Materials Science & Processing》2009,95(4):983-988
An optical backplane based on a meshed polymer waveguide architecture enabling high-speed board-to-board optical interconnection
is presented. This planar array of multimode polymer waveguides can provide passive strictly non-blocking links between server
line cards fitted with optical transmitter and receiver arrays. This architecture offers a scalable and low-cost solution
to the bandwidth limitations faced by electrical backplanes and is suitable for PCB integration. The reported backplane demonstrator
uses a matrix of 100 waveguides each capable of 10 Gb/s operation to interconnect 10 cards for a total capacity of a terabit
per second aggregate data rate in multicast mode. Characterisation of the backplane demonstrator reveals low link losses of
2 to 8 dB for a multimode fibre input and crosstalk values below −35 dB. Error free data transmission at 10 Gb/s is achieved
with a power penalty of only 0.2 dB at a bit-error-rate of 10−9. Additionally, lossless operation of a Gigabit Ethernet link over the backplane is achieved even when using the worst-case
highest loss links. 相似文献
8.
Considering free-space optical communication systems, we analyze the performance of the intensity scintillation of the optical-wave propagation in the slant path under different atmospheric turbulences. Under the zero scale, we derive the log-intensity spatial covariance function of the optical-wave propagation in the slant path through the turbulent atmosphere based on the modified Rytov method. We demonstrate the relationship between the reception performance of the distributed antenna array and the aperture-averaging factor. Furthermore, we also obtain the optimum aperture diameter, number of sub-antennas, and the sub-antenna interval of the array receiver in intermediate turbulence. This study can benefit the design of the receiving system for the optical-wave propagation in the slant path through the turbulent atmosphere in free-space optical communication systems. 相似文献
9.
Nedal Al-Ababneh 《Optics Communications》2006,266(2):473-481
The signal-to-noise ratio (SNR) of integrated planar optical (IPO) board-to-board interconnections system is analyzed. The SNR is derived as a function of separation between the boards, beam spot size, optical system efficiency, receiver thermal noise, thickness of the substrate, and the angle of propagation of the beam. Based on the analyses and the results obtained it is shown that the design of optical interconnects system can be optimized for maximum SNR using at least one parameter, namely, angle of propagation. 相似文献
10.
Optical Review - Aiming at the problem of short transmission distance and large loss in free-space transmission of optical communication data, a research method of optical communication data... 相似文献
11.
Avalanche photodetectors are very important solid-state detectors currently used in long-distance and wide-band optical communication systems, due to their faster speed of response compared to other solid-state photodiodes. Furthermore, it has been found that by using heterostructures one can improve both multiplication gain and quantum efficiency of such a device. DOVATT is a heterojunction impatt device in which there is one avalanche zone followed by two drift zones at different scattering limited velocities. The device is very useful for generation of high power in the X-band.The present paper examines the effect of optical radiation on such a device. Studies have been made on the frequency-response characteristics of the device. The results show that the device has the potentiality of becoming a powerful photodetector in optical communication systems. 相似文献
12.
S. Kaur 《Opto-Electronics Review》2019,27(1):10-13
The welcome and adaptation of optical wireless technology by the modern era has brought forward the concept of an inter-satellite free-space optical communication system. In the present work, I study the combined effect of selection of different operating wavelengths and detector types along with the pointing errors at the transmitter and receiver side on the performance of an inter-satellite free-space optical link. The link performance has been optimized by measuring and analyzing the bit error rate and quality-factor of received signal under different scenarios. Performance of the inter-satellite link has also been investigated considering different modulation formats and data rates for LEO and MEO distances. 相似文献
13.
Kun Yang Zhihua Li Baoxia Li Wei Gao Fengman Liu Jian Song 《Fiber and Integrated Optics》2013,32(3):164-177
Abstract A novel 10-Gbps × 12-channel pluggable parallel optical transceiver is designed and fabricated. Compared with other optical transceivers, this transceiver emphasizes small size, high-density, low power consumption, and high transmission speed. Most importantly, its optical coupling structure is simplified to promote cost-effective large-scale production. This transceiver is electrically pluggable and consists of transmitter and receiver modules linked by parallel multi-mode fibers. Each module consists of a six-layered high-speed, high-density printed circuit board, the size of which is 30 mm × 18 mm × 1 mm, packaged with optoelectronic devices and corresponding control chips. The printed circuit boards not only provide a high-speed electrical connection between the I/O interfaces and high-speed chips, but they also supply power and ground planes to those chips. End-to-end error-free transmission at 10.3125 Gbps was obtained for a 231 ? 1 non-return-to-zero pseudo-random bit sequence. 相似文献
14.
鉴于空间光通信系统中分辨率在很大程度上影响着整个通信系统的性能,而PSD(position sensitive detector)作为APT(acquisition, pointing and tracking)子系统常用的探测器件,具有分辨率高,无盲区,响应速度较快的优点,分析了PSD的基本结构和定位原理,研究了使用PSD作为空间光通信APT子系统粗跟踪技术的位置分辨率,并指出了提高PSD分辨率的着手点。用实验方案对PSD的分辨率进行了具体的实验分析。通过对实验数据分析可知,PSD的平均位置分辨率达到12.6μm,该值与理论分辨率吻合得较好。这说明PSD作为APT子系统精跟踪探测器的可行性。 相似文献
15.
We report on the fabrication of spectrally selective organic photodiodes (OPDs) and present a green sensitive OPD, whose spectral response peaks in the green region between 470 nm and 560 nm, as well as a red sensitive OPD whose spectral response peaks in the red region between 610 nm to 720 nm. We show that the spectral sensitivity of OPDs can be tuned by either choosing organic semiconductors with the appropriate photoresponse or by utilizing adequate device architectures with integrated optical filters. The results demonstrate the great flexibility of organic semiconductor materials. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
16.
Using laser beams with less than perfect spatial coherence is an effective way of reducing scintillations in free-space optical communication links. We report a proof-of-principle experiment that quantifies this concept for a particular type of a partially coherent beam. In our scaled model of a free-space optical communication link, the beam is composed of several partially overlapping fundamental Gaussian beams that are mutually incoherent. The turbulent atmosphere is simulated by a random phase screen imprinted with Kolmogorov turbulence. Our experiments show that for both weak-to-intermediate and strong turbulence an optimum separation between the constituent beams exists such that the scintillation index of the optical signal at the detector is minimized. At the minimum, the scintillation reduction factor compared with the case of a single Gaussian beam is substantial, and it is found to grow with the number of constituent beams. For weak-to-intermediate turbulence, our experimental results are in reasonable agreement with calculations based on the Rytov approximation. 相似文献
17.
星地激光通信中分布式接收阵列的特性研究 总被引:5,自引:0,他引:5
星地激光通信中,发射机对准误差及大气湍流会引起接收信号衰落,对带前置光放大的阵列接收机,分析了分布式接收阵列的抗衰落性能。研究表明,分布式接收阵列对发射机对准误差引起的衰落具有一定抑制作用,阵列中各子接收孔径之间的距离可根据发射机对准误差及湍流的强弱进行优化设计。与传统式阵列相比,分布式阵列可以采用更窄的发射光束宽度,降低对发射功率的要求。分布式阵列的另一个重要特性还在于:当实际发射机对准误差标准差大于设计值时,通过调整阵列各子接收孔径之间的距离,可以在很大程度上降低发射机对准误差引起的功率损失。 相似文献
18.
Xiang Zhou 《中国光学快报(英文版)》2010,(9):863-870
This paper presents a review on the recent progress of digital signal processing (DSP) in the high-speed optical transmission system using single-carrier based multi-level modulation formats. The principle of several digital phase and polarization tracking algorithms recently proposed and demonstrated for future spectrally-efficient optical transmission system are discussed in detail. A novel DSP-based interference mitigation algorithm for the single-ended coherent receiver has been included. Recent technology advance on transmitter-side DSP such as digital pulse-shaping, pre-equalization and digital nonlinear compensation has also been discussed. 相似文献
19.
20.
平面波导型对称星型耦合器的优化设计 总被引:2,自引:1,他引:1
通过有限差分波束传播法(FD-BPM)研究了N×N平面波导型星型耦合器的优化设计思想和方法,并通过17×17星型耦合器的模拟设计证明了它的可行性.给出了在输出端引入辅助波导的方法,以提高输出波导阵列的均匀性.并通过模拟计算,分析了圆心缩入程度和锥形区的形状对输出结果的影响.此法也同样适合于N值更大的星型耦合器. 相似文献