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AbstractA high-sensitivity temperature sensor based upon an optical fiber Fabry-Perot interferometer (FPI) filled with polydimethylsiloxane (PDMS) is reported that employed a single mode fiber (SMF) and a hollow core fiber (HCF) to enhance the sensitivity. The sensing characteristics were investigated from 20 °C to 40 °C. The experimental results demonstrate that the sensor is sensitive to temperature due to the high thermal optical coefficient (TOC) and high thermal expansion coefficient (TEC) of PDMS, achieving a high sensitivity of 2.155 nm/°C. The designed sensor shows great potential for high-precision temperature sensing applications due to its high sensitivity, compact structure, and simple preparation. [ABSTRACT FROM AUTHOR]

Potential of hybrid gold nanoparticles/Graphene Oxide (Au/GO) coatedsingle mode fiber (SMF) sensor by exploiting localized surface plasmon resonance (LSPR) effect for detection of spoiledmilk is studied. Various diametersof SMF’s cladding are prepared ranging from its original size, d=0.1250mm to d=0.1215mm. A mechanical polishing technique using sandpaper is appliedto etch the cladding area in which resultsthe SMF with diameter less than 0.1250mm. Hybrid layers of Au/GO are deposited onto the SMF via drop-casting technique by varies the number of layers of GO between one to five layers, meanwhile Au nanoparticles are kept constant at one layer. To generate LSPR, light with excitation wavelength of 1310nm and 1550nm are transmitted at the first end of Au/GO coated SMFresulting in strong scattering and extinction spectra.The fiber is bend about 8cm in diameter to produce evanescent waves around it. To investigate the sensitivity of sensor in detecting milk’s spoilage condition, the Au/GO bend SMF sensor is immersed into the milk’ssolution which has been exposed to the environment for 24 hours, 48 hours and 72 hours. The maximum optical power response,ΔP%=6.85% isobtained when the one layer of Au/GO coated bend SMF had beenimmersed into the milk solution with exposure time of 24hours. The values of ΔP% decrease about 3.50% and 2.00% respectively with the increment of exposure time at 48 hours and 72 hours.These results indicate the sensing ability of our proposed sensor to detect different levels of spoiled milk as the exposuretime increased.The output of this study validates the main role of LSPR effect in enhancing the sensitivity of Au/GO bend SMF sensor for real time detection of milk’sspoilage.

The fiber nonlinearities are one of the main performance limiting factors in any optical communication system. There are several parameters that effectively contribute in mitigation of these fiber nonlinearities such as fiber dispersion, effective area of fiber core, etc. Here, we have investigated the four wave mixing (FWM) nonlinear impairments in 16-channel WDM system. The FWM crosstalk becomes very critical to handle for long haul transmission systems at high power levels. Here, 16 channels WDM is being implemented and its performance is evaluated in terms of bit error rate (BER), Q factor, etc. for distance transmission upto 500 km. [ABSTRACT FROM AUTHOR]

The transmission of the high data rate and information over the optical fiber is restricted by various dispersion phenomenon which further results into intersymbol interference (ISI). This article proposes two different methodologies for optical fiber deformation aiding vibration monitoring one using the pin diode as a photo-detector device and another manifesting the avalanche photo-detector. The novelty of this article lies in optical signal conversion using photo-detector processing followed by low pass Gaussian filter in order to reduce the extra contortion. This work is approaching electronic dispersion compensation technique (EDC) for compensation of chromatic dispersion at two distinct bit rates of 25 and 30 Gbps over 120 km of single mode fiber. Both the diodes have tested for theory performance using factors like Q-factor, bit error rate and eye height. It is found that pin diode is exhibiting a quality factor of 67.150 and 40.5944 at 25 and 30 Gbps, respectively. When avalanche pin diode is used at the same data rates, quality factor of 73.0240 and 43.3523 are obtained, respectively. Hence, use of avalanche photodiode at high bit rates is utilized and the simulations showed the optimum photo-diode for efficacious dispersion compensation at such a long transmission distance. [ABSTRACT FROM AUTHOR]

Power over fiber (PoF) with sleep mode operation in centralized radio access networks (C-RAN) of low power Remote Radio Heads (RRH) helps to reduce power consumption. This proposal includes bundles of single mode optical fibers (SMF) as part of the 5G C-RAN front-haul solution for providing control on power consumption by selectively activating some parts of the RRH. We experimentally demonstrate a PoF system based on 14.43 km of SMF feed by 2.24 W giving 226 mW electrical power at the RRH for control, battery charge, load operation and communication purposes. A bidirectional control channel is integrated in the central office and the RRH for providing the capability of entering in sleep mode operation and to provide information about the status of the battery and sensing elements at RRH. The optical data uplink/downlink operates over separate optical fibers shared by various RRHs and achieves low power consumption below 33 mW with low data rates. The measured PV cells conversion efficiency is above 30%. The RRH has two sleep modes of operation with a minimum power consumption of 5.8 mW. [ABSTRACT FROM AUTHOR]

An in-line optical fiber Mach-Zehnder interferometer (MZI) sensor with high fringe visibility is reported. The sensor is formed by splicing a short section of four-core fiber (FCF) between two coupling sections. The coupling section is fabricated by cascading very short segment of few mode fiber, multimode fiber (MMF), and large core diameter MMF together. A maximum fringe visibility of approximately 30 dB is obtained in the transmission spectrum. The temperature and curvature sensing response were also experimentally investigated. The temperature sensitivities are 61 pm/°C and 49 pm/°C for dip A and dip B ranging from 30 °C to 80 °C, respectively. The curvature sensitivities for dip A and dip B are 20.77 nm/m−1 and 12.89 nm/m−1 in the range of 0.2983 m−1 to 0.7916 m−1, as well as 9.99 nm/m−1 and 5.38 nm/m−1 from the range of 0.7916 m−1 to 1.039 m−1, respectively. The proposed MZI sensor has the advantage of easy fabrication, compactness, higher fringe visibility, and low cost. [ABSTRACT FROM AUTHOR]

A CO-OFDM system combines the advantages of both coherent detection and OFDM modulation for future high speed fiber transmission. In this paper, we propose an I/Q modulation technique using dual-drive MZMs for high rate 10 Gb/s CO-OFDM system. The proposed modulator provides 10.63 dBm improved optical spectra compared to a single dual-drive MZM. The simulation results in terms of BER and Q factor are quite satisfactory upto a transmission reach of 3,000 km and that to without making use of any dispersion compensation. A BER of about 8.03×10−10 and 15.06 dB Q factor have been achieved at −10.43 dBm received optical power. [ABSTRACT FROM AUTHOR]

A novel fiber-optic sensing structure based on miniaturized modal interferometer (MMI) for simultaneous refractive index (RI), strain and temperature measurement is proposed. It is mainly based on Mach–Zehnder interferometer (MZI) and formed by introducing a down taper between two adjacent up tapers in one single mode fiber (SMF). Experimental results demonstrate a RI sensitivity of 131.93 nm/RIU, a strain sensitivity of 0.0007 nm/ μ ε and a temperature sensitivity of 0.0878 nm/°C respectively. The sensor is merely made of SMF which is cheap and available, and the whole fabrication process contains only cleaving and splicing and can be well controlled by a commercial fiber splicer. [ABSTRACT FROM AUTHOR]

This paper successfully demonstrate point-topoint (P2P) 2.5 TB/s DWDM system in downstream for 100 wavelengths having 0.4nm (50GHz) channel spacing by using post-dispersion compensation scheme. Each channel is transmitting 25GB/s data rate in down link. A 20km dispersion compensating fiber (DCF) followed by 80km standard single mode fiber (SSMF) which passes 20 times through fiber span for compensating the chromatic dispersion. The maximum reach of designed system is (100 × 20) 2,000km. In this paper we also performed the comparison of different modulation formats such as NRZ, RZ and CRZ. It has been observed that CRZ modulation format can achieve BER as better as e-9 for each channel, which gives best performance. The performance of designed system is compared in terms of Q-factor, eye diagrams and BER. [ABSTRACT FROM AUTHOR]

A rigorous modal solution approach based on the numerically efficient finite element method (FEM) has been used to design a tapered photonic crystal fiber with a large mode area that could be efficiently coupled to an optical fiber. Here, for the first time, we report that the expanded mode area can be stabilized against possible fabrication tolerances by introducing a secondary surrounding waveguide with larger air holes in the outer ring. A full-vectorial -field approach is employed to obtain mode field areas along the tapered section, and the Least Squares Boundary Residual (LSBR) method is used to obtain the coupling coefficients to a butt-coupled fiber.

This paper presents the design and analysis of optical filters that are placed at the output of directly modulated vertical cavity surface emitting laser (VCSEL) in the process of inexpensive transmitter's implementation for upcoming generation optical access network. Generation of non return to zero (NRZ) optical signal from the transmitter for 110 km error-free single mode fiber (SMF) transmission at 10 Gb/s with bit error rate (BER) of 10 in the absence of the external modulator and encoder was proposed. Effects of super-Gaussian and Butterworth optical filters at VCSEL output were demonstrated to maximize performance of SMF optical systems without need of any dispersion compensation technique. [ABSTRACT FROM AUTHOR]

This paper presents long reach wavelength division multiplexing passive optical network (WDM-PON) system capable of delivering downstream 20 Gbit/s data and upstream 10 Gbit/s data on a single wavelength. The optical source for downstream data and upstream data is mode locked laser at central office and reflective semiconductor optical amplifier (RSOA) at each optical network unit. We use two RSOAs at each optical network unit for the 10-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 be 45 km by using Erbium-doped fiber amplifiers at the RN.The hybrid amplifier is designed to enhance the signal power and compensated the fiber dispersion over a wide wavelength range. Optical Equalization technique is used before the receiver to improve modulation bandwidth of an RSOA based colorless optical network unit. Optical Equalization technique helps to improve downlink and uplink performance. Author also investigates analysis of backscattered optical signal for upstream data and downstream data simultaneously. Bit error rate, backscattered optical signal power were measured to demonstrate the proposed scheme. In this paper Long reach and large data service aspects of a WDM-PON is presented. [ABSTRACT FROM AUTHOR]

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 [ABSTRACT FROM AUTHOR]

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We investigated the transport of a 16 channels 40 Gb/s dense wavelength division multiplexing (DWDM) system which uses high Raman gain of dispersion compensation fiber (DCF) for long-haul DWDM transmission. Using the return to zero differential phase shift keying (RZ-DPSK) modulation format with an optimized dispersion compensation format, we demonstrate DWDM transmission with a capacity of 640 Gb/s with 0.4 nm channel spacing over 4500 km of transmission fiber. The transmission system structure uses 120 km single mode fiber and 30 km DCF for thirty spans in the C band wavelength range and a Raman Amplifier with high Raman gain to achieve long-haul transmission. We also used enhanced forward error correction for high capacity transmission over several thousand kilometers with the RZ-DPSK modulation format. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2548–2551, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25552 [ABSTRACT FROM AUTHOR]

This article details the evolution of Ethernet into Gigabit Ethernet and how this LAN-based technology has undergone major transformations over time. From its data rates and distances to supported media and functionality, Ethernet has greatly improved, enabling it to surmount many of its former limitations and in so doing to expand beyond the LAN into the MAN and now even the WAN. In this article, Pioneer Consulting explores the evolution further by focusing on some of the major technological directions in the Ethernet equipment industry. [ABSTRACT FROM AUTHOR]

• A modelling, simulation and numerical analysis is presented in this paper for Fabry Perot Interferometer as multiple beam interferometer and it is implemented through MATLAB. • The effect of fiber optic divergence with FPI gap is analyzed. • The effect of geometrical deviation i.e. parallelism and flatness along with reflectivity is analyzed individually as well as their combined effect. • The above mentioned effects on the characteristic of FPI are calculated in terms of finesse and visibility. • The proposed analytical method is experimentally verified. An FPI is made with thin film broad band coated sapphire and commercially available wafer of Silicon. It is illuminated by a broad band optical signal through an optical fiber, and reflected signal is analyzed by grating based optical spectrometer. Fiber optic (FO) Fabry Perot Interferometer (FPI) is a common technique in the optical sensing domain. FPI is a multiple beam interferometer and thus has good finesse, i.e. better resolution of frequency selection/rejection in the transmission/reflection mode. It is well established that high reflectivity as well as flatness of both the interferometric surfaces along with high degree of parallelism among them are essential to achieve high finesse and high visibility in the FPI. But most of the FO-FPIs have low to medium finesse. To the best of our knowledge, quantitative analysis of the effect of flatness and parallelism on the FO-FPI is not reported earlier. In this paper a numerical analysis technique is presented to analyze the behavior of FO-FPI for the above discussed parameters. The number of interfering beams is limited by threshold intensity of the reflected beams. Individual effects of divergence, reflectivity and flatness of FPI surfaces, and parallelism error among both the surfaces as well as their combined effect are explored here. These effects are quantified in terms of variation in visibility and finesse of FPI. An FPI of gap 50 µm, optical fiber of 50 µm core with 0.21 NA and 51% reflectivity at both the surfaces are considered in the analysis. The characteristic of an ideal FPI is compared to FPIs having imperfections such as FO divergence, shape error of 50 nm, parallelism error of 100 nm and their combined effects. The calculated finesse of these FPIs are around 5, 4.136, 4.3, 3.198 and 3.17 respectively. To experimentally verify the model, an FPI is fabricated with broadband thin film coated sapphire and commercially available Silicon wafer as the two reflecting surfaces. The theoretical interference pattern closely matches with the experimental one of the fabricated FPI. [ABSTRACT FROM AUTHOR]