This paper presents a long-reach orthogonal frequency division multiplexing wavelength division multiplexing passive optical network (OFDM WDM-PON), a system capable of delivering 100  Gb/s of data downstream and 2  Gb/s of data upstream on a single wavelength. The optical sources for downstream data and upstream data are a continuous-wave laser at a central office and a reflective semiconductor optical amplifier (RSOA) at each optical network unit.

Poor power quality can cause serious problems causing malfunction, instability, short lifetime, memory loss and data errors of sensitive loads etc. Electric power quality has become an important issue now days. To improve the power quality, sources of disturbances as well as detection techniques must be known. The purpose of this paper is to present different detection techniques for sag, swell, harmonics and make comparison between them. Signal processing techniques are used to extract features from measured data and detect triggering points or transition segment of disturbances.

The image fusion is the process of combining relevant information from two or more images into a single image. The resulting image will be more informative than any of the input images. A new approach for object extraction from high-resolution images is presented in this report. In this paper, we have presented image fusion based on wavelet transform.

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It addresses orthogonal frequency division multiplexing (OFDM) transmission over optical links with high spectral efficiency, i.e. by using high-order quadrature amplitude modulation (QAM) schemes as a mapping method prior to the OFDM multicarrier representation. Here we address especially coherent optical OFDM modem in long distance which is affected by nonlinear distortion caused by fiber nonlinearity. Fiber nonlinearity is a majo performance-limiting factor in advanced optical communication systems. We proposed a nonlinear electrical equalization scheme based on the Volterra model. To compare with other popular linear compensation technique such as the least mean square (LMS), simulation results are presented to demonstrate the capability of a Volterra model based electrical equalizer used in a coherent optical orthogonal frequency division multiplexing system. It is shown that the Volterra model based equalizer can significantly reduce nonlinear distortion.

This article presents Long Reach Wavelength Division Multiplexing Passive Optical Network (WDM‐PON) system capable of delivering downstream 2 Gbit/s data and upstream 70 Gbit/s data on a single wavelength using pulse source which is mode locked laser that generates a single pulse of “sech” shape with specified power and width. That is, soliton pulse. The optical source for downstream data and upstream data is sech pulse generator at central office (CO) and reflective semiconductor optical amplifier (RSOA) at each optical network unit (ONU). We use two RSOAs at each ONU for the 70‐Gb/s upstream transmission. The operating wavelengths of these RSOAs are separated by the free‐spectral range of the cyclic arrayed waveguide gratings used at the CO and remote node (RN) for (de)multiplexing the WDM channels. We extend the maximum reach of this WDM PON to be 123 km by using Erbium‐doped fiber amplifiers at the RN. The results show that the error‐free transmission can be achieved for all WDM channels in the wavelength range of >35 nm with sufficient power margins. We also investigate analysis of backscattered optical signal for upstream data and downstream data simultaneously. Bit error rate, were measured to demonstrate the proposed scheme. In this article, Long reach and large data service aspects of a WDM‐PON is presented. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2853–2859, 2013

Keywords:Discrete cosine transformed (DCT), peak-signal-to-noise-ratio (PSNR), secret reference matrix (SRM)

This article presents long reach wavelength division multiplexing passive optical network (WDM‐PON) system capable of delivering 100 Gb/s data to each subscriber. For cost‐effectiveness, WDM‐PON is implemented in loopback configuration using directly modulated reflective semiconductor optical amplifiers (RSOAs) at 25 Gb/s. We use four RSOAs at each optical network unit for the 100‐Gb/s upstream transmission. The operating wavelengths of these RSOAs are separated by the free‐spectral range of the cyclic arrayed waveguide gratings used at the central office and remote node (RN) for (de)multiplexing the WDM channels. We extend the maximum reach of this WDM‐PON to 123 km by using Erbium‐doped fiber amplifiers at the RN. The results show that the error‐free transmission can be achieved for all WDM channels in the wavelength range of >35 nm with sufficient power margins. Bit error rate and Q‐factor were measured to demonstrate the proposed scheme. In this article, long reach and large data service aspects of an access network are presented. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1426–1430, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27581 DOI 10.1002/mop.27572