- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Comparative analysis of capacity oriented Integrated AMI modulation technique for the deployment of radio over fiber system
摘要： To improve the spectral efficiency and to reduce non-linear distortion in the optical system, various advanced modulation techniques have been investigated for radio over fiber (RoF) system. The investigation indicates the high data rate distortion less transmission for long-haul RoF system still further investigation is required to improve spectral efficiency and to get the reduction in signal degradation. In this paper, an advanced modulation technique referred as integrated alternate mark inversion modulation technique based upon external modulation (electro-absorption modulator) has been designed and simulated. The results show better performance in terms of performance metrics i.e. Q-factor (25.15) and BER (4e-140) and also enhance the data transmission capabilities up to 100 Gbps covering the long distance of 250 km resulting a reasonable reduction in signal degradation particularly chromatic dispersion effects for long-haul transmissions.
关键词： Single mode fiber—SMF,Carrier suppressed return to zero—CSRZ,Erbium doped fiber amplifier—EDFA,RoF,Dispersion compensating fiber—DCF,Multi-mode fiber—MMF
更新于2025-09-23 15:23:52
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Estimation of Signal-to-Cross Talk Ratio of Stimulated-Raman-Scattering-Induced Cross Talk in Wavelength-Division-Multiplexing-Based Radio-over-Fiber Links
摘要： This paper evaluates the signal-to-cross talk ratio (SXR) of cross talk induced by stimulated Raman scattering (SRS) in radio-over-fiber (RoF) systems based on wavelength-division multiplexing. The reported study has modeled the relations of SXR to modulation frequency, optical power, transmission length, and effective area of fiber for various values of the walk-off parameter. The summary of experimental reveals that SXR decreases with increases in channel input power and transmission distance and increased with increases in fiber effective area and modulation frequency. Results showed that increasing the walk-off parameter from 13.6 to 81.6 ps/km increased the SXR by almost 6 dBm. Furthermore, various fibers, including standard single-mode fiber (SMF), Corning LEAF, and Alcatel TeraLight were tested for their capacity to mitigate SRS-induced cross talk. These tests demonstrated that standard SMF suppressed SRS cross talk effectively and offered values of SXR 3 dBm and 6 dBm higher than the values exhibited by Alcatel TeraLight and Corning LEAF, respectively.
关键词： wavelength-division multiplexing (WDM),signal-to-cross talk ratio (SXR),stimulated Raman scattering (SRS),single-mode fiber (SMF),radio over fiber (RoF)
更新于2025-09-23 15:22:29
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Sherman-Morrison Formula Aided Adaptive Channel Estimation for Underwater Visible Light Communication With Fractionally-sampled OFDM
摘要： In this paper, we investigate the channel estimation (CE) problem in an underwater visible light communication (UVLC) system invoking fractionally-sampled optical orthogonal frequency division multiplexing (FS-OOFDM). In practical UVLC scenarios, the communication links inevitably suffer from many stochastic channel effects including multi-path dispersion, scattering, turbulence, etc., and/or from the mobility of the transceiver, therefore resulting in a time-varying, location-dependent non-stationary propagation environment. Naturally, compared with the indoor visible light communication (VLC) scenario with a typical assumption being the time-flat channel models, it becomes a notable challenge for designing a low-complexity adaptive CE in the much more complicated UVLC scenarios. To solve this problem, we derive a class of Bayesian CE algorithms referred to as the Sherman-Morrison formula (SMF) based CE (SMF-CE), by exploiting the property of rank-one structure of the second-order channel statistics in the delay domain. Furthermore, an adaptive version of SMF-CE (ASMF-CE) can be obtained through updating the imperfect a priori knowledge of the channel and the noise’s statistics. Simulation results demonstrate the superior performances of the proposed algorithms in comparison to existing methods, while maintaining a reduced computational complexity in comparison to the conventional linear minimum mean square error (LMMSE) scheme.
关键词： Sherman-Morrison formula (SMF),Channel estimation (CE),underwater visible light communication (UVLC),fractional sampling (FS),optical orthogonal frequency division multiplexing (OOFDM)
更新于2025-09-23 15:21:01
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Analysis of Four Wave Mixing Effects in 16 ??10 Gb/S WDM Optical Communication System
摘要： 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.
关键词： passive optical networks (PONs),single mode fiber (SMF),four wave mixing (FWM)
更新于2025-09-19 17:13:59
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All-fiber sub-20a??ps ultra low repetition rate high peak power mode-locked fiber laser to generate supercontinuum
摘要： We report an ultra-low repetition rate self-started mode-locked fiber laser at 1.55 μm spectral region with a sub-20 ps pulse duration at repetition rate of less than 100 kHz leading to high energy and peak power pulses. A repetition rate of 13.8 kHz with the pulsewidth of 17 ps is then achieved and the issue of multiple pulses is mitigated in the linear cavity structure by proper selection of semiconductor saturable absorber and dispersion management in the cavity. A broad supercontinuum achieved using 7 m SM-ZBLAN fiber while pumping with mode-locked fiber laser with repetition rate, pulsewidth, pulse energy and peak power of 53 kHz, 12.5 ps, 16.6 μJ and 1.3 MW, respectively.
关键词： mode-locked fibre laser,ultra low repetition rate,high peak power pulsed laser,ZBLAN single mode fiber (SMF),supercontinuum
更新于2025-09-16 10:30:52
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Enhancement of Signals Characteristics with Least Effect of Optical Communication Losses for Dense Optical Communication Systems
摘要： In this paper, the major aim is to enhance the bandwidth and therefore increase the capacity of the optical fibre communication system by reducing the dispersion in the fibre. Dispersion compensation is necessary to reduce losses and cost of the system. In this paper, we are basically focusing on reducing or decreasing chromatic dispersion. Chromatic dispersion is a type of dispersion in which pulse broadening occurs due to delay in different spectral components. We here make use of dispersion compensated fibre (DCF) for reducing the dispersion in the WDM system. Here, we basically use three dispersion compensated techniques (pre-compensation, post-compensation and mix compensation). The comparison in the three models of dispersion compensated technique is made in terms of transmission power vs. Q factor and also transmission power vs. Bit Error Rate.
关键词： DCF,MMF,WDM,SMF,quality factor,BER,optical amplifier
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Multi-Band Optical Systems to Enable Ultra-High Speed Transmissions
摘要： Current forecasts indicate that the fastest growing IP-traf?c is in metro and data center interconnect (DCI) [1]. The exploitation of the entire low-loss spectrum of single-mode ?bers (SMF) (from 1260 nm up to 1620 nm) was proposed to avoid the predictable capacity crunch and the eventual need for a new ?bre infrastructure roll-out. First analytic result considering multi-band (MB) transmission (from O- to L-band) hint an achievable traf?c load exceeding 200 Tb/s for a 500 km link in a single SMF [2]. The maximum transmittable capacity over ITU-T G.652D SMF, which is the mainly deployed ?ber type [3], is evaluated in this work. Three different ?ber span lengths are considered: 40 km, 60 km and 80 km. A high level overview of the MB setup is depicted in Fig. 1 (left). The system is composed of a MB transmission bench composed of {L, C, S, E, O}-band transmitters. 50 GHz spaced polarization multiplexed (PM)-MQAM signals with root raised cosine shaping (roll-off = 0.15) and a symbol rate of 32 Gbaud are multiplexed and launched into the ?ber link. A 2 nm guard-band between adjacent bands is assumed. At the receiver side, the bands are de-multiplexed, ampli?ed and then demodulated. We assume lumped ampli?ers: Praseodymium doped ?bre ampli?er(DFA) in O-band [4], Bismuth DFA in E-band [5], Thulium DFA in S-band [6] and Erbium DFA in C- and L-bands. A noise ?gure of 6, 5.5, 7, 6 and 7 dB are assumed for {L, C, S, E, O}-band ampli?ers, respectively. The wavelength ranges and number of channels in each band are reported in Table 1. The local-optimization global-optimization (LOGO) approach [7] is employed to optimize the launched power. The overall signal-to-noise-ratio (SNR) is estimated considering the impact of non-linear interference (NLI) which is evaluated using the generalized Gaussian noise (GGN) model [8]. The GGN model takes into account the frequency dependence of the ?ber loss, the chromatic dispersion and the stimulated Raman scattering (SRS). Finally, the achievable capacity assuming a ?exible transceiver capable to completely exploit the available SNR is computed.
关键词： ultra-high speed transmissions,ITU-T G.652D SMF,capacity crunch,single-mode fibers,multi-band optical systems
更新于2025-09-11 14:15:04
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[IEEE 2018 International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET) - Chennai, India (2018.3.22-2018.3.24)] 2018 International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET) - Integration of Visible Light Communication and Fiber Communication System
摘要： In this paper, we present an integrated fiber and visible light communication (VLC) system with both single and multimode fibers. Before establishing the fiber–VLC link, we implement a fiber link alone and achieve least BER for a particular length of the fiber. This fiber length is taken as an optimum performing link. The main performance measure utilized in this paper is the Bit Error Rate (BER). Optimum performance is achieved at the point of minimum BER. For an optimum performing fiber–VLC link, the dispersion is analyzed and the compensation of chromatic dispersion is done using ideal dispersion compensation Fiber Bragg Grating (FBG). Utilizing the Gray coded input sequence instead of direct binary sequence reduces the BER, since adjacent constellation points will only differ in one bit. The BER results for 16 QAM (Quadrature Amplitude Modulation) and 64 QAM using Orthogonal Frequency Division Multiplexing (OFDM) are compared for both single mode fiber and multimode fiber links. The simulation results show that for Single Mode Fiber–VLC (SMF–VLC) link the dispersion compensation is better when compared to the Multi Mode Fiber–VLC (MMF–VLC) link.
关键词： Dispersion Compensation FBG,BER,fiber–VLC link,Gray coded input,SMF–VLC,MMF–VLC
更新于2025-09-09 09:28:46