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[IEEE 2018 International Conference on Advanced Science and Engineering (ICOASE) - Duhok (2018.10.9-2018.10.11)] 2018 International Conference on Advanced Science and Engineering (ICOASE) - An ICI Reduction Based on PAPR Clipping in Coherent Optical OFDM System
摘要： The Inter-Carrier Interference (ICI) compensation for Coherent Optical Orthogonal Frequency Division Multiplexing (CO-OFDM) system has been studied in this paper. The purpose behind is to investigate the presence of ICI due to the impact of Laser Phase Noise (LPN) and Fiber Non-Linearity (FNL). Thereby, we propose a simple clipping scheme which represents an effective distortion algorithm to decrease the Peak to Average Power Ratio (PAPR) for 4QAM system. The method exhibits a significant process on ICI cancellation in CO-OFDM system. The OFDM signal is basically transmitted along 550km distance rated at 10Gbps single mode fiber for the coherent optical mode. The new findings show that the receiver sensitivity is highly improved below 10-3 FEC for laser power 5dBm; and archives about 1dBm to 2.4dBm when laser power becomes 8dBm at a typical clipping ratio of 0.6. In particular, the system exhibits a good performance over a 385km transmission distance in comparison to the conventional CO-OFDM. As a result, the proposed clipping shows that the system can enhance its the performance by reducing ICI in the CO-OFDM system; in addition to present a high robustness in BER metric against FNL by a clear reduction in PAPR.
关键词： Coherent Optical Orthogonal Frequency Division Multiplexing (CO-OFDM),Inter-Carrier Interference (ICI),Peak to Average Power Ratio (PAPR),Fiber Nonlinearity (FNL),Bit Error Rate (BER),Laser Phase Noise (LPN)
更新于2025-09-23 15:22:29
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A Versatile Silicon-Silicon Nitride Photonics Platform for Enhanced Functionalities and Applications
摘要： Silicon photonics is one of the most prominent technology platforms for integrated photonics and can support a wide variety of applications. As we move towards a mature industrial core technology, we present the integration of silicon nitride (SiN) material to extend the capabilities of our silicon photonics platform. Depending on the application being targeted, we have developed several integration strategies for the incorporation of SiN. We present these processes, as well as key components for dedicated applications. In particular, we present the use of SiN for athermal multiplexing in optical transceivers for datacom applications, the nonlinear generation of frequency combs in SiN micro-resonators for ultra-high data rate transmission, spectroscopy or metrology applications and the use of SiN to realize optical phased arrays in the 800–1000 nm wavelength range for Light Detection And Ranging (LIDAR) applications. These functionalities are demonstrated using a 200 mm complementary metal-oxide-semiconductor (CMOS)-compatible pilot line, showing the versatility and scalability of the Si-SiN platform.
关键词： transceiver,silicon photonics,Kerr nonlinearity,optical phased array,Coarse Wavelength Division Multiplexing (CWDM),multiplexing,LIDAR,silicon nitride,beam steering,frequency comb,grating coupler
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE International Ultrasonics Symposium (IUS) - Kobe, Japan (2018.10.22-2018.10.25)] 2018 IEEE International Ultrasonics Symposium (IUS) - Love Wave Mode Resonator with a Wide Stable Temperature Range
摘要： One-port Love wave mode resonator has the potential of a wireless sensing platform for measuring physical or chemical parameters because of its sensitivity to mass loading and enhanced sensing areas. Nevertheless, the frequency shift of the sensor due to the working temperature attracts much attention. To design a Love wave mode wireless sensor using one-port resonator with the better temperature compensation characteristics, a layered structure of ZnO/IDT+SiO2/quartz with embedded electrodes is proposed. The amorphous SiO2 is filled in the grooves between the electrodes for temperature compensation on the quartz substrate. Taking account of the third-order nonlinear elastic constants of quartz, ZnO, SiO2 and Al, respectively, a one-port Love wave sensor with relative frequency shift less than 25ppm in the temperature range of 25℃~100℃ is obtained.
关键词： temperature stability,third-order elastic constant,nonlinearity,Love wave resonator
更新于2025-09-23 15:22:29
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A Highly Birefringent and Nonlinear AsSe<formula><tex>$_{2}$</tex></formula>-As<formula><tex>$_{2}$</tex></formula>S<formula><tex>$_{5}$</tex></formula> Photonic Crystal Fiber with Two Zero-Dispersion Wavelengths
摘要： A hybrid AsSe2–As2S5 photonic crystal ?ber (PCF) with a solid elliptical core is proposed and studied theoretically by the full-vector ?nite element method. The core and cladding of the PCF are made of AsSe2 and As2S5 glasses, respectively. Simulation results demonstrates that, at the operating wavelength of 1.55 μm, the proposed PCF not only exhibits a very high birefringence of 0.091 but also has large nonlinear coef?cients of 147.8 and 78.2 W ?1m ?1 for the X- and Y-polarized (X and Y-pol) modes, respectively. Moreover, it is able to achieve two zero-dispersion wavelengths for both the X-pol (1.52 and 2.19 μm) and Y-pol (1.43 and 2.12 μm) modes. The proposed hybrid PCF exhibits excellent polarization maintaining and the nonlinearity performance, thus, suitable to be used in supercontinuum spectrum generation and polarization maintaining nonlinear signal processing.
关键词： zero-dispersion wavelength,High birefringence,supercontinuum spectrum generation,photonic crystal ?ber,nonlinearity
更新于2025-09-23 15:22:29
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Analogue Wireless Beamforming Exploiting the Fiber-Nonlinearity of Radio Over Fiber Based C-RANs
摘要： As a key technique of supporting the fixed backbone network, radio over fiber (RoF) systems transmit the radio frequency signals over optical fiber in order to take advantage of their large available bandwidth. In this context, optical fiber aided phased antenna array (PAA) based beamforming techniques have attracted substantial research interest with the goal of improving the cell-edge coverage of cellular base stations. In this paper, we conceive a novel optical fiber aided beamforming technique based on the fiber's nonlinearity to be applied in cloud radio access network (C-RAN). In our proposed technique, the PAA elements are fed by the phase-shifted signals introduced by our highly nonlinear fiber (HNLF) aided phase-shifting solution, which results in an angular beamsteering range of around 90°. This can be exploited by sectorization in cellular networks to reduce the cochannel interference imposed. Furthermore, we exploit the proposed RoF-aided phase shifting technique in C-RAN, where our proposed system takes advantage of the centralized signal processing capability of the RoF system to conceive an all-optical processing based tunable beamforming system. While our flexible HNLF-aided phase-shifting process is confined to the central office of the C-RAN, the end users in the C-RAN cellular networks are capable of flexibly choosing the serving remote radio heads (RRHs) and employing diverse wireless transmission techniques. Through integrating our HNLF-aided phase-shifting design into the proposed C-RAN, we impose as little as 0.1 dB signal-to-noise Ratio (SNR) degradation compared to its traditional electronic counterpart, which requires extra phase-shifters.
关键词： phase-shifter,self-phase modulation,phased array antenna beamforming,C-RAN,cross-phase modulation,highly nonlinear fiber,Optical fiber,optical nonlinearity
更新于2025-09-23 15:22:29
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Nonlinear Noise of Low Transmission Penalty Dual-Stage Discrete Raman Amplifier
摘要： We experimentally characterise the linear and nonlinear performance of a >70nm, dual-stage, 19.5dB average net gain discrete Raman amplifier using different nonlinear fibres in the second stage. We propose an architecture built with a combination of IDF and SMF, and compare its performance with amplifiers built with conventionally used nonlinear fibre types (IDF-IDF, IDF-DCF). The measured FWM product power shows the IDF-SMF architecture to generate less nonlinear interference when compared to other schemes. We test the amplifiers with 5x120Gb/s DP-QPSK WDM signals in a recirculating loop at 10 recirculations of 93.4km SMF fibre, where the power sweep shows up to 2dB optimum launch power difference, with the maximum Q2 factor varying by up to 1.6dB. Using the optimum transmission point we measure a Q2=8.8dB at 35 recirculations of 93.4km transmission (3269km) with the proposed IDF-SMF scheme, which is >460km further than the other tested architectures. All characterised schemes performed similarly in the linear noise regime.
关键词： Broadband Transmission,Discrete Raman Amplification,Nonlinearity Characterisation
更新于2025-09-23 15:21:21
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Analytic Mode Normalization for the Kerr Nonlinearity Parameter: Prediction of Nonlinear Gain for Leaky Modes
摘要： Based on the resonant-state expansion with analytic mode normalization, we derive a general master equation for the nonlinear pulse propagation in waveguide geometries that is valid for bound and leaky modes. In the single-mode approximation, this equation transforms into the well-known nonlinear Schr?dinger equation with a closed expression for the Kerr nonlinearity parameter. The expression for the Kerr nonlinearity parameter can be calculated on the minimal spatial domain that spans only across the regions of spatial inhomogeneities. It agrees with previous vectorial formulations for bound modes, while for leaky modes the Kerr nonlinearity parameter turns out to be a complex number with the imaginary part providing either nonlinear loss or even gain for the overall attenuating pulses. This nonlinear gain results in more intense pulse compression and stronger spectral broadening, which is demonstrated here on the example of liquid-filled capillary-type fibers.
关键词： resonant-state expansion,Kerr nonlinearity,leaky modes,nonlinear pulse propagation,waveguide geometries
更新于2025-09-23 15:21:21
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Characterization of the Piezoresistive Effects of Silicon Nanowires
摘要： Silicon nanowires (SiNWs) have received attention in recent years due to their anomalous piezoresistive (PZR) effects. Although the PZR effects of SiNWs have been extensively researched, they are still not fully understood. Herein, we develop a new model of the PZR effects of SiNWs to characterize the PZR effects. First, the resistance of SiNW is modeled based on the surface charge density. The characteristics of SiNW, such as surface charge and effective conducting area, can be estimated by using this resistance model. Then, PZR effects are modeled based on stress concentration and piezopinch effects. Stress concentration as a function of the physical geometry of SiNWs can amplify PZR effects by an order of magnitude. The piezopinch effects can also result in increased PZR effects that are at least two times greater than that of bulk silicon. Experimental results show that the proposed model can predict the PZR effects of SiNWs accurately.
关键词： nonlinearity,silicon nanowire,surface depletion effects,piezoresistive effects
更新于2025-09-23 15:21:21
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Optical Gaussons for nonlinear logarithmic Schr?dinger equations via the variational iteration method
摘要： In this work, we study the logarithmic Schr?dinger equation, with and without a detuning term. We derive optical Gaussons, named for their Gaussian shape, for these logarithmic models via using the variational iteration method. The obtained Gaussons are characterized by no soliton radiation, and propagate through dispersion-managed optical fibers. The physical structures of the derived Gaussons, namely, its amplitude and width will be examined for a variety numerical values of the parameters.
关键词： Schr?dinger equation,Logarithmic nonlinearity,Optical fibers,Gaussons
更新于2025-09-23 15:21:21
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Anisotropic third-order nonlinearity in pristine and lithium hydride intercalated black phosphorus
摘要： Two-dimensional (2D) black phosphorus (BP) displays unique anisotropic properties in its linear optical responses, but its third-order nonlinearity (Kerr effect) has remained relatively unexplored. Here we measured the third-order nonlinear optical responses in exfoliated BP and in lithium hydride intercalated BP (LiH-BP) flakes using polarization-resolved microscopic femtosecond Z-scan technique. Strong optical Kerr nonlinearities were measured for single flakes of BP and LiH-BP, with third-order nonlinear susceptibilities that are larger than many 2D materials. The nonlinear coefficients of LiH-BP are higher than those of BP, indicating that lithium hydride intercalation enhances not only the ambient stability of BP but also its nonlinear optical response. Highly anisotropic polarization-dependent Kerr nonlinearities of both BP and LiH-BP flakes were observed. The strong nonlinear and anisotropic optical responses of BP and LiH-BP indicate great potential of these materials in nonlinear photonics device applications.
关键词： in-plane anisotropy,nonlinear optical responses,lithium hydride intercalated black phosphorus,Kerr nonlinearity,Black phosphorus
更新于2025-09-23 15:21:21