Advances in Optical Technologies

Optical computing is a very interesting 60-year old field of research. This paper gives a brief historical review of the life of optical computing from the early days until today. Optical computing generated a lot of enthusiasm in the sixties with major breakthroughs opening a large number of perspectives. The period between 1980 and 2000 could be called the golden age with numerous new technologies and innovating optical processors designed and constructed for real applications. Today the field of optical computing is not ready to die, it has evolved and its results benefit to new research topics such as nanooptics, biophotonics, or communication systems.

Pierre Ambs

Optical Computing: A 60-Year Adventure

光学计算：60年探索之旅

Minimizing the bright/shadow focal spot size for differently polarized incident waves through the additional apodization of the focusing system output pupil by use of an optical element with the vortex phase dependence on angle and the polynomial amplitude dependence on radius is studied. The coefficients of the radial polynomial were optimized with the aim of fulfilling certain conditions such as the energy efficiency preservation and keeping the side lobes under control. The coefficients were chosen so as to minimize the functional using Brent’s method.

S. N. Khonina

S. G. Volotovskiy

Minimizing the Bright/Shadow Focal Spot Size with Controlled Side-Lobe Increase in High-Numerical-Aperture Focusing Systems

在高数值孔径聚焦系统中通过控制旁瓣增加来最小化亮/暗焦点尺寸

Photonic signal processing is used to implement common mode signal cancellation across a very wide bandwidth utilising phase modulation of radio frequency (RF) signals onto a narrow linewidth laser carrier. RF spectra were observed using narrow-band, tunable optical filtering using a scanning Fabry Perot etalon. Thus functions conventionally performed using digital signal processing techniques in the electronic domain have been replaced by analog techniques in the photonic domain. This technique was able to observe simultaneous cancellation of signals across a bandwidth of 1400 MHz, limited only by the free spectral range of the etalon.

David M. Benton

Photonic Processing for Wideband Cancellation and Spectral Discrimination of RF Signals

用于射频信号宽带抵消和频谱鉴别的光子处理

Laser microwelding has been an essential tool with a reputation of rapidity and precision for joining miniaturized metal parts. In industrial applications, an accurate prediction of weld bead geometry is required in automation systems to enhance productivity of laser microwelding. The present work was conducted to establish an intelligent algorithm to build a simplified relationship between process parameters and weld bead geometry that can be easily used to predict the weld bead geometry with a wide range of process parameters through an artificial neural network (ANN) in laser microwelding of thin steel sheet. The backpropagation with the Levenberg-Marquardt training algorithm was used to train the neural network model. The accuracy of neural network model has been tested by comparing the simulated data with actual data from the laser microwelding experiments. The predictions of the neural network model showed excellent agreement with the experimental results, indicating that the neural network model is a viable means for predicting weld bead geometry. Furthermore, a comparison was made between the neural network and mathematical model. It was found that the developed neural network model has better prediction capability compared to the regression analysis model.

Mohd Idris Shah Ismail

Yasuhiro Okamoto

Akira Okada

Neural Network Modeling for Prediction of Weld Bead Geometry in Laser Microwelding

激光微焊接中焊缝几何形状预测的神经网络建模

With the increasing input power in optical fibers, the dispersion problem is becoming a severe restriction on wavelength division multiplexing (WDM). With the aid of solitons, in which the shape and speed can remain constant during propagation, it is expected that the transmission of nonlinear ultrashort pulses in optical fibers can effectively control the dispersion. The propagation of a nonlinear ultrashort laser pulse in an optical fiber, which fits the high-order nonlinear Schrödinger equation (NLSE), has been solved using the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:msup><mml:mrow><mml:mi>G</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant="normal">'</mml:mi></mml:mrow></mml:msup><mml:mo>/</mml:mo><mml:mi>G</mml:mi></mml:math> expansion method. Group velocity dispersion, self-phase modulation, the fourth-order dispersion, and the fifth-order nonlinearity of the high-order NLSE were taken into consideration. A series of solutions has been obtained such as the solitary wave solutions of kink, inverse kink, the tangent trigonometric function, and the cotangent trigonometric function. The results have shown that the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:msup><mml:mrow><mml:mi>G</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant="normal">'</mml:mi></mml:mrow></mml:msup><mml:mo>/</mml:mo><mml:mi>G</mml:mi></mml:math> expansion method is an effective way to obtain the exact solutions for the high-order NLSE, and it provides a theoretical basis for the transmission of ultrashort pulses in nonlinear optical fibers.

Jiang Xing-Fang

Wang Jun

Wei Jian-Ping

Hua Ping

Application of the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:msup><mml:mrow><mml:mi>G</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant="normal">'</mml:mi></mml:mrow></mml:msup><mml:mo>/</mml:mo><mml:mi>G</mml:mi></mml:math> Expansion Method in Ultrashort Pulses in Nonlinear Optical Fibers

<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:msup><mml:mrow><mml:mi>G</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant="normal">'</mml:mi></mml:mrow></mml:msup><mml:mo>/</mml:mo><mml:mi>G</mml:mi></mml:math>展开法在非线性光纤中超短脉冲的应用

Tunable microoptics deals with devices of which the optical properties can be changed during operation without mechanically moving solid parts. Often a droplet is actuated instead, and thus tunable microoptics is closely related to microfluidics. One such device/module/cell type is an optical shutter, which is moved in or out of the path of the light. In our case the transmitting part comprises a moving transparent and electrically conductive water droplet, embedded in a nonconductive blackened oil, that is, an opaque emulsion with attenuation of 30 dB at 570 nm wavelength over the 250 μ m long light path inside the fluid (15 dB averaged over the visible spectral range). The insertion loss of the cell is 1.5 dB in the “open shutter” state. The actuation is achieved via electrowetting-on-dielectrics (EWOD) with rectangular AC voltage pulses of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:mn fontstyle="italic">2</mml:mn><mml:mo>·</mml:mo><mml:mn fontstyle="italic">90</mml:mn></mml:math> V peak-to-peak at 1 kHz. To flexibly allow for horizontal, vertical, and diagonal droplet movement in the upright x-y plane, the contact structures are prepared such that four possible stationary droplet positions exist. The cell is configured as two capacitors in series (along the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M4"><mml:mrow><mml:mi>z</mml:mi></mml:mrow></mml:math> axis), such that EWOD forces act symmetrically in the front and back of the 60 nl droplet with a response time of &lt;20 ms.

Henning Fouckhardt

Johannes Strassner

Carina Heisel

Dominic Palm

Christoph Doering

Microfluidic Optical Shutter Flexibly <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mrow><mml:mi>x</mml:mi></mml:mrow></mml:math>-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mrow><mml:mi>y</mml:mi></mml:mrow></mml:math> Actuated via Electrowetting-on-Dielectrics with &lt;20 ms Response Time

微流控光学快门：通过介电润湿实现灵活的<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mrow><mml:mi>x</mml:mi></mml:mrow></mml:math>-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mrow><mml:mi>y</mml:mi></mml:mrow></mml:math>驱动，响应时间<20毫秒

Thermal effects are the main obstacle to getting high power and good beam quality in diode end-pumped solid-state lasers. In this work, a theoretical investigation of thermal effects in single and dual end-pumped solid-state lasers is carried out using finite element analysis (FEA) for a selected number of widely used laser producing materials, namely, Nd:YAG, Yb:YAG, and Nd:KGW. Crystals with different dimensions are also investigated both in single and in dual end-pumped configuration. Finally, the effect of using composite crystals on thermal lensing is investigated. An experiment to measure the thermal focal length for two different crystals was carried out and a comparison with FEA computed focal length of the thermal lens is made. In all cases studied in this work, results show clear effects of thermal lensing with some differences depending on crystal type, pump power, and size.

Moustafa Sayem El-Daher

Finite Element Analysis of Thermal Effects in Diode End-Pumped Solid-State Lasers

二极管端面泵浦固体激光器中热效应的有限元分析

Raman scattering has been used to study the influence of 2.45 GHz microwave on the structure of water. It has been shown that treatment of the distilled water samples by electromagnetic field leads to long-term changes in the vibrational density of states. It was established that the retention time of structural changes of the water samples depends on the sample volume. The experimental results have been interpreted on the basis of the percolation model. It has been suggested that the change in the chemical composition of the water treated by microwaves can lead to a change in the structure of the percolation cluster formed by the network of hydrogen bonds. The time of the equilibrium structure recovery of the percolation cluster after termination of the microwaves depends on the cluster size and is much slower than the recovery in the chemical composition of water.

A. V. Yakunov

M. M. Biliy

A. P. Naumenko

Long-Term Structural Modification of Water under Microwave Irradiation: Low-Frequency Raman Spectroscopic Measurements

微波辐照下水长期结构变化的低频拉曼光谱测量

Currently it is not possible to create a fully optical communication system without a software tool which simulates an optical communication line in real conditions prior to its construction. The aim of this article is to establish a comparison between the EDFA (erbium doped fibre amplifier) and SOA (semiconductor optical amplifier) optical amplifiers in the WDM (wavelength division multiplexing) system. The system contains a four-channel WDM with speed of 10 Gbps and optical fibre with length of 80 km. Simulations are conducted in the programme environment “ OptSim .” The quality of the optical communication system is evaluated by the BER (bit error rate) and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mrow><mml:mi>Q</mml:mi></mml:mrow></mml:math>-factor for individual wavelengths, namely, of 1558 nm and 1562 nm, which are within the C-band.

Tomáš Ivaniga

Petr Ivaniga

Comparison of the Optical Amplifiers EDFA and SOA Based on the BER and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mrow><mml:mi>Q</mml:mi></mml:mrow></mml:math>-Factor in C-Band

基于C波段中BER和Q因子的EDFA与SOA光放大器比较

Digital technology has transformed the information flow and support infrastructure for numerous application domains, such as cellular communications. Cinematography, traditionally, a film based medium, has embraced digital technology leading to innovative transformations in its work flow. Digital cinema supports transmission of high resolution content enabled by the latest advancements in optical communications and video compression. In this paper we provide a survey of the optical network technologies for supporting this bandwidth intensive traffic class. We also highlight the significance and benefits of the state of the art in optical technologies that support the digital cinema work flow.

Sajid Nazir

Mohammad Kaleem

Optical Network Technologies for Future Digital Cinema

未来数字电影的光网络技术

出版信息	出版商: Hindawi Limited，出版周期: ，期刊类型: journal，开源期刊: 否
基本数据	创刊年份: 2010，原创研究文献占比: ，自引率:， Gold OA占比:

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