The viability of subcarrier modulation for enhancing the performance of installed-base MMF links

The technique of Subcarrier Modulation is assessed by statistical analysis as a viable solution to broadband data transmission over dispersion limited multimode fibre. It is shown that a suitable passband region for transmission of 2.5 Gb/s channels exists at 5 GHz in greater than 80% of worst-case fibres under standard SMF/MMF launch conditions. ©2002 Optical Society of America.

A polymeric regenerative optical bus for board-level optical interconnections

A scalable polymer waveguide-based regenerative optical bus architecture for use in board-level communications is presented. As a proof-of-principle demonstration, a 4-channel polymer bus formed on a FR4 substrate providing 10 Gb/s/channel data transmission is reported. © 2012 OSA.

Low-cost PCB-integrated 10-Gb/s optical transceiver built with a novel integration method

A novel integration method for the production of cost-effective optoelectronic printed circuit boards (OE PCBs) is presented. The proposed integration method allows fabrication of OE PCBs with manufacturing processes common to the electronics industry while enabling direct attachment of electronic components onto the board with solder reflow processes as well as board assembly with automated pick-and-place tools. The OE PCB design is based on the use of polymer multimode waveguides, end-fired optical coupling schemes, and simple electro-optic connectors, eliminating the need for additional optical components in the optical layer, such as micro-mirrors and micro-lenses. A proof-of-concept low-cost optical transceiver produced with the proposed integration method is presented. This transceiver is fabricated on a low-cost FR4 substrate, comprises a polymer Y-splitter together with the electronic circuitry of the transmitter and receiver modules and achieves error-free 10-Gb/s bidirectional data transmission. Theoretical studies on the optical coupling efficiencies and alignment tolerances achieved with the employed end-fired coupling schemes are presented while experimental results on the optical transmission characteristics, frequency response, and data transmission performance of the integrated optical links are reported. The demonstrated optoelectronic unit can be used as a front-end optical network unit in short-reach datacommunication links. © 2011-2012 IEEE.

Characteristics and applications of InGaN micro-light emitting diodes on Si substrates

InGaN micro-light emitting diodes on Si substrates have been fabricated and characterized. Their abilities for micro-display, high modulation bandwidth of 270 MHz and data transmission rate of up to 400 Mbit/s have been demonstrated. © 2013 IEEE.

A polymeric regenerative optical bus for board-level optical interconnections

A scalable polymer waveguide-based regenerative optical bus architecture for use in board-level communications is presented. As a proof-of-principle demonstration, a 4-channel polymer bus formed on a FR4 substrate providing 10 Gb/s/channel data transmission is reported. © 2012 OSA.

A 40 Gb/s optical bus for optical backplane interconnections

Optical technologies have received large interest in recent years for use in board-level interconnects. Polymer multimode waveguides in particular, constitute a promising technology for high-capacity optical backplanes as they can be cost-effectively integrated onto conventional printed circuit boards (PCBs). This paper presents the first optical backplane demonstrator based on the use of PCB-integrated polymer multimode waveguides and a regenerative shared bus architecture. The backplane demonstrator is formed with commercially-available low-cost electronic and photonic components onto conventional FR4 substrates and comprises two opto-electronic (OE) bus modules interconnected via a prototype regenerator unit. The system enables interconnection between the connected cards over four optical channels, each operating at 10 Gb/s. Bus extension is achieved by cascading OE bus modules via 3R regenerator units, overcoming therefore the inherent limitation of optical bus topologies in the maximum number of cards that can be connected to the bus. Details of the design, fabrication, and assembly of the different parts of this optical bus backplane are presented and related optical and data transmission characterisation studies are reported. The optical layer of the OE bus modules comprises a four-channel three-card waveguide layout that is compatible with VCSEL/PD arrays and ribbon fibres. All on-board optical paths exhibit insertion losses below 13 dB and intra-channel crosstalk lower than -29 dB. The robustness of the signal distribution from the bus inputs to all respective bus output ports in the presence of input misalignment is demonstrated, while 1 dB input alignment tolerances of approximately ±10 μm are obtained. The electrical layer of the OE bus modules comprises the essential driving circuitry for 1×4 VCSEL and PD arrays and the corresponding control and power regulation circuits. The interface between the optical and electrical layers of the bus modules is achieved with simple OE connectors that enable end-fired optical coupling into and out of the on-board polymer waveguides. The backplane demonstrator achieves error-free (BER < 10-12) 10 Gb/s data transmission over each optical channel, enabling therefore, an aggregate interconnection capacity of 40 Gb/s between any connected cards. © 1983-2012 IEEE.

First demonstration of a full C-band tunable WDM-PON system with novel high-temperature DS-DBR lasers

We demonstrate automatic operation of a cooler-less tunable-laser based WDM-PON system. Using a pilot-tone based overhead channel and centralized wavelength locking scheme, 1 Gb/s and 10 Gb/s data transmission is demonstrated in a multi-user set-up. © 2013 Optical Society of America.

Low Power Integrated Circuits for Wireless Neural Recording Applications

A group of prototype integrated circuits are presented for a wireless neural recording micro-system. An inductive link was built for transcutaneous wireless power transfer and data transmission. Power and data were transmitted by a pair of coils on a same carrier frequency. The integrated receiver circuitry was composed of a full-wave bridge rectifier, a voltage regulator, a date recovery circuit, a clock recovery circuit and a power detector. The amplifiers were designed with a limited bandwidth for neural signals acquisition. An integrated FM transmitter was used to transmit the extracted neural signals to external equipments. 16.5 mW power and 50 bps - 2.5 Kbps command data can be received over 1 MHz carrier within 10 mm. The total gain of 60 dB was obtained by the preamplifier and a main amplifier at 0.95Hz - 13.41 KHz with 0.215 mW power dissipation. The power consumption of the 100 MHz ASK transmitter is 0.374 mW. All the integrated circuits operated under a 3.3 V power supply except the voltage regulator.

Implantable Microsystem for Wireless Neural Recording Applications

A prototype microsystem is presented for wireless neural recording application. An inductive link was built for transcutaneous wireless power transfer and data transmission. Total 16.5 mW power and 50 bps - 2.5 Kbps command data can be received over 1 - 5 MHz with a distance of 0-10 mm. The integrated amplifiers were designed with a limited bandwidth for neural signals acquisition. The gain of 60 dB was obtained by preamplifier at 7 Hz - 3 KHz. An integrated FM transmitter was used to transmit the extracted neural signals to external equipments with 0.374 - 2 mW power comsumption and a maximum data rate of 500 Kbps at 100 MHz. All the integrated circuits modules except the power recovery circuit were tested or stimulated under a 3.3 V power supply, and fabricated in standard CMOS processing.

A 5GHz low power WLAN transceiver SiGe RFIC for personal communication terminal applications

A low-cost low-power single chip WLAN 802.11a transceiver is designed for personal communication terminal and local multimedia data transmission. It has less than 130mA current dissipation, maximal 67dB gain and can be programmed to be 20dB minimal gain. The receiver system noise figure is 6.4dB in hige-gain mode.

基于RTI的车辆定位仿真系统数据传输研究

目前分布式体系结构的研究重点是提高系统的可扩展性、互操作性和可重用性，而对于实时性要求高的分布式仿真系统，还需要在HLA体系结构基础上，考虑如何提高系统的数据传输效率，以满足实时性要求。本文从应用层角度出发，从以下两个方面研究了改进策略： 一，从数据交互方面考虑，为了提高分布式仿真系统内部有效数据传输效率，满足系统实时性要求，以车辆定位仿真系统为问题原型，提出一种基于运行时间支撑系统数据分发管理（RTI-DDM）和套接字(Socket)的双层数据传输模型：一方面利用RTI-DDM来限定传输数据的范围，依据待交互的数据值域对数据的发送和接收进行过滤，有效降低系统内部冗余数据的传输；另一方面，利用Socket技术在仿真实体之间建立点对点的直接传输，从而提高系统的运行效率。对比实验结果表明，在相同的仿真交互数据量下，该模型相对于传统单层RTI数据传输模型，数据传输延时平均缩短70%。 二，从时间管理方面考虑，本文通过实验验证的方法，分析不同时间管理策略对仿真系统的数据传输和运行控制的影响，并针对车辆定位仿真系统中联邦成员之间的数据交互和逻辑控制关系特点，选择合适的时间管理策略，保证数据因果关系的正确性，进一步提高了系统的数据传输性能。 实验和应用结果表明，本文提出的改进策略简单有效，提高了系统数据传输效率，较好的解决了基于HLA/RTI的定位仿真系统的实时性问题。

Polyelectrolyte complexes based on chitosan and poly(L-glutamic acid)

Polyelectrolyte complexes (PECs) were prepared by mixing aqueous solutions of chitosan (CS) and poly(L-glutamic acid) (PLGA) at various pH. It was found that the stoichiometry of the PECs depends on pH.An investigation of the PECs using Fourier transform infrared spectroscopy proved that the formation of the complexes is due to electrostatic interaction between –NH3 + groups of CS and –COO− groups of PLGA. The solid PECs were characterized using wide-angle X-ray diffraction, which suggested that a strong interaction occurs between the two polymers at pH = 4 or 5 and relatively weak interaction at pH = 3. These results were further confirmed by thermogravimetric analysis data. Transmission electron microscopy showed that the complexes have a spherical shape. The effect of ionic strength on the size of the PECs was also studied using dynamic light scattering. It was found that the size of the PECs is dependent on pH.

载人潜器半物理虚拟仿真系统及其性能分析

为了缩短深海载人潜器控制系统的开发周期,测试系统性能,根据载人潜器的自身特点,构建和实现了载人潜器所有传感器、执行器设备模拟,以及潜器在海底实景的运动状态的半物理虚拟仿真系统。首先,以仿真系统的硬件架构和数据流程为基础,重点介绍了潜器设备模拟的软件体系结构;其次,在仿真平台上测试了各种网络数据的传输延迟,分析了其整体性能;最后,得出了潜器控制器设计的时间约束。现阶段整个系统已经开发成功,并投入运行到潜器控制系统的安装调试中。

载人潜器串口设备转接工业以太网的实时性建模与分析

根据具体的需求,为载人潜器设计了一种基于工业以太网的内部数据通讯和控制系统,其数据通讯的实时性是衡量控制系统的一个重要指标,因此,为了分析串行数据通信系统的实时性能,据其选用的传感器和网络架构的特点,建立了串口数据包传送时间延迟的数学模型;并在潜器平台上,以实测数据试验误差验证了该模型的准确性和普遍性,从而为开发人员对各种串口设备的参数设置提供理论指导;最后用该模型分析了载人潜器串行数据传送的实时性。

基于信道估计的RS纠错编码改进算法的设计与实现

提出了一种基于信道估计的RS纠错编码改进算法,该算法可以自适应地根据外界条件和环境对传输信道的干扰变化实时地调节编码系统的数据冗余量。仿真与完整的分析结果证实了该改进算法有效地改善了RS编码算法的传输效率;并且通过实际应用表明:良好的性能,高容错性适应于该通信系统的多种传输信道,具有很强的实用性。