- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Application of MoWS2-rGO/PVA thin film as all-fiber pulse and amplitude modulators in the O-band region
摘要： In this work, a MoWS2-rGO/PVA thin film is fabricated and its applications as in amplitude modulation are demonstrated. Embedded in a praseodymium fluoride fiber laser cavity, the MoWS2-rGO/PVA thin film is able to induce pulsing in the laser output, which operates in the O-band region. As an optical amplitude modulator, the MoWS2-rGO/PVA thin film is capable of achieving a modulation efficiency of 0.17 dB/mW in the O-band region over a pump power range of 46.0 mW to 78.5 mW. C-band and L-band operation is also demonstrated, with modulation efficiencies of 0.30 dB/mW and 0.15 dB/mW, respectively over pump power ranges of 3.51 mW–52.17 mW and 24.4 mW–61.3 mW. This work can be improved by further engineering the composition ratio of the alloy material to enhance the modulation efficiency for both pulsed and amplitude modulations, giving rise to various applications, in particular in bio-medicine and manufacturing.
关键词： Amplitude modulator,MoWS2-rGO/PVA thin film,Pulse modulator,O-band
更新于2025-11-28 14:23:57
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[IEEE 2018 XXIIIrd International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory (DIPED) - Tbilisi, Georgia (2018.9.24-2018.9.27)] 2018 XXIIIrd International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory (DIPED) - The Nonuniquness of Solutions to the Synthesis Problems of Plane Array by the Prescribed Amplitude Directivity Pattern
摘要： Studies of a nonlinear synthesis problem for plane equidistant array by the prescribed amplitude directivity pattern (DP) are presented. A characteristic feature of problems of this class is the non-uniqueness and branching of solutions depending on the physical parameters of array. The existence of several types of real solutions is shown. More effective complex solutions branch off from such solutions. The methods of finding the curves of branching the solutions and the numerical algorithms to search the optimal synthesized amplitude DPs are presented.
关键词： amplitude DP,non-uniqueness and branching of solutions,curves of branching,Synthesis problem,plane array
更新于2025-09-23 15:23:52
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Performance Limits of FSO Based SAC-OCDMA System Under Weather Conditions
摘要： In this paper, the Spectral Amplitude Coding Optical Code Division Multiple Access (SAC-OCDMA) is investigated in Free Space Optics (FSO) using Zero Cross Correlation (ZCC) codes to evaluate its performance limits in terms of link range. The system is analyzed under clear, haze, moderate fog and dense fog weather conditions. This system has been evaluated numerically and by simulation analysis by maintaining the transmitted power at 10 dBm, for safety reason, according to International Telecommunication Union (ITU) and minimum acceptable BER of 10–9. The simulation results shown that the present system can transmit 622 Mbps/1 Gbps up to maximum link range of 1450 m/1100 m and 61 m/54 m under clear and dense fog conditions, respectively.
关键词： fog,haze,free space optic (FSO),spectral amplitude coding optical code division multiple access (SAC-OCDMA),zero cross-correlation (ZCC)
更新于2025-09-23 15:23:52
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Approaching Terabits per Carrier Metro-Regional Transmission Using Beyond-100GBd Coherent Optics with Propabilistically Shaped DP-64QAM Modulation
摘要： This research work proposed and experimentally demonstrated beyond-100GBd probabilistically-shaped coherent optics that support transmission of ~1.2 Tbps coded line rate and ~0.9 Tbps net bit rate per optical carrier over metro-regional distances. Pursuing next-generation transmission systems having both high capacity approaching Terabits per wavelength and high spectral efficiency requires engineering efforts from different aspects, which may includes the enhancement of analog-to-digital or digital-to-analog (AD/DA) interfaces, the improvement of channel characteristics, and also the realization of better receiver sensitivities, preferably through DSP techniques such as probabilistic shaping (PS). By doing so, this work achieved single-channel and 112.5GHz-WDM transmission of 900G wavelengths over 800 km and 400 km, respectively, which employed PS DP-64QAM modulation format at 105 GBd, yielding a net spectral efficiency of 8.05 bits/s/Hz. Such a high symbol rate was demonstrated using a commercially available DAC unit without band-interleaving. The enhanced optical channel consists of ITU-T G.654 compliant Terawave SLA+ fiber spans with backward-pumped Raman amplifiers. In addition, with the same PS DP-64QAM modulation format and the same enhanced channel, this research work also demonstrated that 400G wavelengths can be delivered over 2,800 km supporting long-haul applications.
关键词： quadrature amplitude modulation,probabilistic shaping,optical fibers,Coherent optical communications
更新于2025-09-23 15:23:52
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[Communications in Computer and Information Science] Futuristic Trends in Network and Communication Technologies Volume 958 (First International Conference, FTNCT 2018, Solan, India, February 9–10, 2018, Revised Selected Papers) || Future Perspectives in Elastic Optical Networks
摘要： The new generation Elastic Optical Networks (EONs) based on Orthogonal Frequency Division Multiplexing (OFDM) can accommodate exponentially increasing heterogeneous data traffic efficiently and economically. In EONs, the optimum channel spacing between various subcarriers is very crucial for its efficient performance. The use of Sub-Carrier Multiplexing (SCM) in EONs is visualized as an evolving field. This paper present the evaluation of SCM based EONs for both mathematical and simulative model. The designed SCM-EON network is analytically evaluated for its performance with different modulation techniques (Direct Modulation and External Modulation). The performance of system is also evaluated for amplification using Semiconductor Optical Amplifier (SOA) and Erbium Doped Fiber Amplifier (EDFA). Simulative results show that Optical Phase Modulation (OPM) along with EDFA offers enhanced performance for the proposed model. It has also been observed that OPM is a better technique for SCM and hence it can be deduced that the combination will boost EONs efficiency in handling network resources.
关键词： SCM,Elastic Optical Networks,OFDM,EDFA,OPM,Bandwidth variable-wavelength cross-connects (BV-WXC),Quadrature Amplitude Modulation (QAM),Coherent Optical Orthogonal Frequency Division Multiplexing (CO-OFDM),Mach-Zehnder modulator (MZM)
更新于2025-09-23 15:23:52
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A structure-simplified and cost-effective coherent receiver for high splitting downstream transmission in next-generation PONs
摘要： In this paper we demonstrate a structure-simplified and cost-effective coherent receiver scheme for high splitting downstream transmission in next generation passive optical networks (NG-PONs). In such scheme, the simple 3dB coupler is used to replace 90° optical hybrid and the electrical local oscillator (LO) is utilized to down-convert signal, and there by only one balanced photodiode (BPD) is required for each polarization. Hence the cost is reduced effectively for the high splitting PON downstream transmission scenario. The comprehensive numerical simulation results show that the receiver sensitivity for both 14G Baud PM-QPSK and PM-16QAM system is comparable to that of the conventional coherent receiver using 90° hybrid. Furthermore, the effect of fiber nonlinearity on maximum power budget performance is investigated. In addition, the high receiver sensitivity of the scheme is also experimentally validated for PM-QPSK and PM-16QAM system under the scenario of 14G Baud BtB, 20km and 40km standard single-mode fiber (SSMF) transmission. The coexistent advantages of low-cost and high receiver sensitivity make the proposed scheme an attractive candidate for NG-PONs.
关键词： Downstream transmission,NG-PONs,Coherent receiver,Quadrature amplitude modulation
更新于2025-09-23 15:23:52
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High-precision FBG demodulation using amplitude ratio curve with sharp peak
摘要： For the fiber Bragg grating (FBG) sensor based on the reflection peak position searching demodulation algorithms, a key problem is that the demodulation precision of measurement signal is seriously limited by the full width half maximum (FWHM) of the FBG reflection spectrum. In this paper, in order to overcome this problem and enhance the measurement precision, we proposed a high-precision demodulation method based on amplitude ratio curve to instead of the FBG reflection spectrum, which can increase the sensing precision significantly. In this method, the Bragg wavelength of FBG is modulated periodically with a sinusoidal function to obtain a series of reflection spectra. Then at each wavelength the amplitude ratio between second harmonic frequency component and fundamental frequency component is calculated to create the amplitude ratio curve. Here, we present a comprehensive theoretical analysis and experimental demonstration to verify the advantages of this method. Comparing with the demodulation method based on the FBG reflection spectrum, the average maximum measure error (MME) of Bragg wavelength is reduced from ± 1.54 pm to ± 0.15 pm, which improved by 10.3 times. In addition, the influence of the modulation amplitude and sampling frequency on demodulation accuracy are also studied in this paper.
关键词： Amplitude ratio curve,High precision temperature measurement,Fiber Bragg grating
更新于2025-09-23 15:23:52
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High-spectral-efficiency 600-Gbps/carrier Transmission Using PDM-256QAM Format
摘要： High-capacity carrier signals with high-order modulation are being considered for data center interconnection (DCI) applications as they can reduce the cost per bit by decreasing the number of devices and increasing fiber capacity. However, signal quality degradation due to device imperfections affecting the frequency response has limited the capacity per carrier of PDM-256QAM signals to under 400 Gbps. Here, it is possible to use a calibration method for dealing with device imperfections wherein a fixed equalizer separately calibrates the frequency response of the transmitter and receiver. Our previous study showed that PDM-256QAM signals at up to 48 GBaud could be transmitted over 100 km, while it used an experimental setup with total 3-dB analog bandwidth of 13 GHz and 20 GHz for transmitter and receiver, respectively. A micro-integrable tunable laser assembly (μITLA) with a typical linewidth of 20 kHz, maximum under 100 kHz. Actual data center interconnection (DCI) applications, however, are expected to use dense wavelength division multiplexing (WDM), so in this study, we examined transmission of 10-WDM 48-GBaud PDM-256QAM signals in a 50-GHz grid and evaluated the WDM penalties. The resulting spectral efficiency (SE) of 600-Gbps/carrier WDM transmissions was as high as 12.02 bit/s/Hz.
关键词： optical,digital coherent,fiber,optical transmission,signal processing,digital communication,high-order quadrature amplitude modulation
更新于2025-09-23 15:23:52
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An 82-m 9 Gb/s PAM4 FSO-POF-UWOC Convergent System
摘要： With the increasing demands in free-space/underwater environmental monitoring, disaster precaution, and manufacturing industry applications, free-space optical (FSO)-plastic optical fiber (POF)-underwater wireless optical communication (UWOC) convergence is designed to be a promising framework for providing long-haul free-space with underwater links. An 82-m 9 Gb/s four-level pulse amplitude modulation (PAM4) system employing a 405-nm blue-light injection-locked laser diode (LD) is thereby offered and practically demonstrated. Results reveal that a 1.8-GHz 405-nm blue-light injection-locked LD can be effectively applied for a 9 Gb/s PAM4 signal transmission over 50 m FSO link, 30 m graded-index (GI)-POF transportation, and 2 m clear ocean underwater channel. To the authors’ understanding, this study is the first to practically build an 82-m 9 Gb/s PAM4 FSO-POF-UWOC convergent system that effectively constructs a long-haul optical wireless-wired-wireless link using doublet lenses, GI-POF, and optical beam reducer. The performances of the proposed convergent systems are analyzed by bit error rate and non-return-to-zero eye diagram in real-time over an 82-m transport. This framework is the leading one to establish a long-haul FSO-POF-UWOC convergent system with qualified transmission performances. It guides a promising way to facilitate wide applications in the convergence of FSO, POF and UWOC.
关键词： Graded-index plastic optical fiber,Underwater wireless optical communication,Four-level pulse amplitude modulation,Free-space optical
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE 3rd Optoelectronics Global Conference (OGC) - Shenzhen (2018.9.4-2018.9.7)] 2018 IEEE 3rd Optoelectronics Global Conference (OGC) - High Speed Novel Hybrid Modulation Technique of Visible Light Communication Based on Artificial Neural Network Equalizer
摘要： Visible light communication (VLC) which realizes data transmission and universal illumination simultaneously has attracted much attention recently. However, the transmission rate of the VLC remains low due to the low bandwidth performance and inter-symbol interference (ISI). Therefore, a hybrid approach using pulse amplitude modulation and pulse width modulation in conjunction with an artificial neural network (ANN) equalizer is proposed, which can theoretically increase the transmission rate by 4 times compared with the traditional way, and provide variable brightness to realize the integration of data transmission and illumination control. In addition, an artificial neural network equalizer is proposed to undo the effects of ISI, considering that the bandwidth of the LED is only 3MHz. Without the ANN equalizer, the maximum transmission rate of the proposed hybrid modulation link only reaches 36 Mbps under the condition of no signal processing; however, with the ANN equalizer, the transmission speed can up to 2.6 Gbps. The proposed system not only achieves a genuine combination of data transmission and control illumination levels, but also realizes a high data rate with less complexity.
关键词： code division multiple access,pulse amplitude modulation,visible light communication,artificial neural network equalizer
更新于2025-09-23 15:23:52