- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Optical and Digital Key Enabling Techniques for SDM-Based Optical Networks
摘要： In order to support, in a cost-effective way, the data capacity demand in the context of future 5G networks, a new set of advanced technologies need to be explored, as it is the case of space-division multiplexing (SDM) along with energy efficient coherent detection based modulation formats. This paper presents the recent results on enabled optical networks based on SDM for high capacity optical networks compatible with 5G network infrastructure and data center connectivity. In particular, we demonstrate the viability of using Long-Period Gratings (LPGs) in multi-core fibers (MCFs) to develop different components for multicore-based SDM systems, such as pump couplers and core/wavelength selective multi-core switches and couplers. Moreover, we also present and characterize the performance of different digital signal processing (DSP) algorithms and subsystems supporting optical coherent detection in SDM systems.
关键词： Coherent detection,long period grating,generalized Stokes space,digital signal processing,space-division multiplexing,space-division demultiplexing
更新于2025-09-23 15:23:52
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FPGA-Based Implementation of an Artificial Neural Network for Measurement Acceleration in BOTDA Sensors
摘要： In recent years, using distributed fiber-optic sensors based on Brillouin scattering, for monitoring pipelines, tunnels, and other constructional structures have gained huge popularity. However, these sensors have a low signal-to-noise ratio (SNR), which usually increases their measurement error. To alleviate this issue, ensemble averaging is used which improves the SNR but in return increases the measurement time. Reducing the noise by averaging requires hundreds or thousands of scans of the optical fiber; hence averaging is usually responsible for a large percent of the entire system latency. In this paper, we propose a novel method based on artificial neural network for SNR enhancement and measurement acceleration in distributed fiber-optic sensors based on the Brillouin scattering. Our method takes the noisy Brillouin spectrums and improves their SNR by 20 dB, which reduces the measurement time significantly. It also improves the accuracy of the Brillouin frequency shift estimation process and its latency by more than 50% in comparison with the state-of-the-art software and hardware solutions.
关键词： Artificial neural network (ANN),digital signal processing,optical fibers,curve fitting,field-programmable gate arrays (FPGAs)
更新于2025-09-23 15:23:52
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Leakage Mitigation in Heterodyne FMCW Radar for Small Drone Detection With Stationary Point Concentration Technique
摘要： To prevent potential hazards posed by fast-evolving drones, it is of importance to develop a radar system for drone detection. Frequency modulated continuous wave (FMCW) radars are widely used for that purpose. Heterodyne architectures are preferred for them to mitigate dc offset errors. Having said that, FMCW radars suffer from permanent leakage from the transmitter into the receiver. The leakage phase noise raises the total noise floor and limits the radar sensitivity. Here, we propose a stationary point concentration (SPC) technique in order to overcome the challenges. The SPC technique concentrates the leakage phase noise on a stationary point to alleviate the impact of the noise. The technique can be realized using digital signal processing without additional hardware. The results show that the proposed technique significantly lowers the noise floor.
关键词： heterodyne,down-conversion,leakage,digital signal processing (DSP),frequency modulated continuous wave (FMCW) radar,stationary point concentration (SPC) technique,stationary point,phase noise,noise floor
更新于2025-09-23 15:22:29
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LUT-Free Carrier Recovery for Intradyne Optical DPSK Receivers in udWDM-PON
摘要： We present an LUT-free carrier recovery architecture for intradyne optical DPSK receivers that reduces the required DSP hardware resources, power consumption as well as total process clocks, aimed at cost-effective transceivers for access networks applications. The proposed architecture simplifies frequency compensation algorithm to avoid using mth-power operation and LUTs. We prototyped the proposed carrier recovery on a commercial FPGA for real-time evaluation with data at 1.25Gb/s. The optical transmission system is implemented by direct-phase modulation of commercial DFB lasers, 25 km of single-mode fiber, and a coherent receiver with low-cost optical front-end based on 3x3 coupler and three photodiodes providing phase-diversity operation. Results show high performance in real-time, achieving -54 dBm sensitivity at BER = 10-3 as well as feed-forward frequency error correction, high robustness against the fast frequency laser drifts, and high tolerance to optical phase noise in a 6.25GHz spaced ultra-dense WDM grid.
关键词： phase shift keying,FPGA,digital signal processing,Carrier recovery,frequency estimation
更新于2025-09-23 15:22:29
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Significant improvement on electrical properties of BaSi <sub/>2</sub> due to atomic H passivation by radio-frequency plasma
摘要： We demonstrate for the ?rst time an intensity-modulated direct-detection link using four states of polarization. The four data-independent tributaries are each assigned distinct states of polarization to enable the receiver to separate the signals. Polarization rotation due to propagation over optical ?ber is tracked and compensated with simple digital signal processing in Stokes space. Transmission below the forward error correction limit is shown for maximum net bitrates of 100 Gb/s (4 × 27 GBd) and 120 Gb/s (4 × 32 GBd) over 2-km standard single-mode ?ber at a center wavelength of 1550 nm.
关键词： direct detection (DD),intensity modulation (IM),digital signal processing,Stokes space,100G,polarization
更新于2025-09-23 15:21:01
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Monitoring of the Ceramic Kerf During the Laser Cutting Process through Piezoelectric Transducer
摘要： Advanced ceramics are widely used in industry due to their unique properties. However, the machining of ceramic components by conventional methods is difficult due to their high level of hardness and brittleness. In this sense, laser beam machining (LBM) is presented as an alternative to conventional methods, enabling the machining of workpieces through more accurate and less invasive techniques. Despite the advantages of laser machining, the process still needs to be studied in detail, as advanced ceramic machining is considered a stochastic process. Thus, real-time monitoring systems are required in order to optimize the ceramic laser machining. Therefore, this paper proposes a novel method for monitoring the cutting kerf in the laser cutting process of ceramic components using a low-cost piezoelectric transducer (PZT) and digital signal processing. Tests were performed on the surface of an alumina ceramic workpiece under different machining conditions. The cutting kerf was measured by a digital microscope and the raw signals from the PZT transducer were collected at a sampling rate of 2 MHz. Time domain and frequency domain analyses were performed in order to find a frequency band that best correlates with the process conditions. Finally, a linear regression was calculated in order to correlate the PZT signal and the measured kerf. The results showed that the piezoelectric transducer was sensitive to the acoustic activity generated during the process, allowing the real-time monitoring of the cutting kerf. Thus, the approach proposed in this paper can be used efficiently in the monitoring of the laser cutting process.
关键词： monitoring,digital signal processing,ceramic,laser machining,piezoelectric transducer
更新于2025-09-23 15:21:01
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - A New DSP-Based Physical Layer Encryption Technique Applied to Passive Optical Networks
摘要： Point-to-multipoint architecture poses serious security problems to passive optical networks (PONs). In this paper, we propose the use of a new digital signal processing (DSP)-based technique to improve the confidentiality of signals traveling through PONs. The technique consists of phase-shifting and delaying the spectral components of baseband signals that further modulate optical carriers. Our simulation analysis encompasses the application of the technique to binary phase-shift keying (BPSK) in an intensity modulated- direct detection (IM-DD) system. Results reveal that the encrypted signals may be properly decoded even when 64 PON users are considered and suggest the potential of the proposed technique for practical implementations. From a security point of view, we show that the proposed technique utterly outperforms the Advanced Encryption Standard (AES) in brute force attacks.
关键词： passive optical networks,physical layer security,digital signal processing
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Precursor reaction method with high Ga Cu(In,Ga)(S,Se) <sub/>2</sub> to achieve increased open-circuit voltage
摘要： Direct detection transceivers offer advantages, including low cost and complexity, in short- and medium-haul links. We carried out studies seeking to identify the signal formats which offer the highest information spectral densities and maximum transmission distances for direct detection links. The performance of two spectrally efficient optical signal formats, single-sideband (SSB) Nyquist pulse-shaped subcarrier modulation (SCM) and SSB orthogonal frequency-division multiplexing (OFDM), are compared by means of simulations. The comparison is performed for a range of wavelength-division multiplexing (WDM) net information spectral densities up to 2.0 b/s/Hz by varying the signal bandwidth, modulation cardinality, and WDM channel spacing. The signal formats’ tolerance to signal–signal beating interference, resulting from square-law detection, is investigated, and the Nyquist-SCM format is found to suffer lower penalties from this nonlinearity at high information spectral densities. In 7 × 28 Gb/s WDM transmission at 2.0 b/s/Hz (with electronic pre-distortion and EDFA-only amplification), Nyquist-SCM signals can be transmitted over distances of up to 720 km of standard SMF in comparison to a maximum of 320 km with the OFDM signal format.
关键词： Digital signal processing,direct detection,wavelength division multiplexing,subcarrier modulation,electronic pre-distortion,optical communication,Nyquist pulse shaping,signal–signal beating interference,orthogonal frequency division multiplexing
更新于2025-09-23 15:19:57
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Time-resolved frequency chirp control of semiconductor lasers using digital signal processing
摘要： The theoretical possibility of precisely controlling the time-resolved chirp in a directly modulated semiconductor laser using a single drive digital-to-analog converter (DAC) controlled via a novel digital signal processing (DSP) algorithm is investigated. A semi-analytical expression for the requisite drive current is obtained through algebraic back-calculation of the large signal laser rate equations, in tandem with a ?rst-order numerical approximation of the optical power and chirp functional relationship. A 25-GHz peak-to-peak frequency modulation (FM) at a bit-rate of 28-Gb/s is demonstrated at a 6 dB extinction ratio, while completely suppressing the transient chirp contribution. Furthermore, a bipolar frequency chirp signal resulting in a di?erential phase shift keying (DPSK) modulation format at a bit-rate of 28-Gb/s was achieved with an error vector magnitude (EVM) below 1%. A 5-bit look-up table (LUT) was found to be adequate for capturing the requisite DSP drive current needed to fully suppress the transient chirp as demonstrated by preliminary optical link simulations at 28-Gb/s.
关键词： Time-resolved frequency chirp,Adiabatic chirp,Digital signal processing,Transient chirp,Directly modulated semiconductor laser
更新于2025-09-23 15:19:57
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Shaping pulses of radiation detectors into a true Gaussian form
摘要： A digital shaper for conversion of detector pulses with a short leading edge and a long exponential tail into a true Gaussian form is proposed and analysed in this paper. The width of Gaussian pulses can be several times smaller than the rise time of the input pulses, i.e. considerably shorter than the undistorted output pulses provided by standard shapers. The algorithm of the true Gaussian shaper is presented in the paper. The output pulses and noises of the true Gaussian shapers are compared with those of standard shapers for different widths of shaped pulses. The analyses has shown that the true Gaussian shaping can be advantageous for detection of strongly overlapped pulses which appear at high particle fluxes in the detector input.
关键词： Digital signal processing (DSP),Electronic detector readout concepts (solid-state),Solid state detectors,Nuclear instruments and methods for hot plasma diagnostics
更新于2025-09-19 17:15:36