In this paper, we have evaluated a bidirectional wavelength division multiplexing passive optical network(WDM-PON) employing intensity modulated/direct detection optical orthogonal frequency division multiplexing(IM/D...In this paper, we have evaluated a bidirectional wavelength division multiplexing passive optical network(WDM-PON) employing intensity modulated/direct detection optical orthogonal frequency division multiplexing(IM/DD-OFDM). The proposed system employs 100 Gbit/s 16 quadrature amplitude modulation(16-QAM) downstream and 5 Gbit/s on-off keying(OOK) upstream wavelengths, respectively. The proposed system is considered low-cost as non-coherent IM/DD OFDM technology and a simple reflective semiconductor optical amplifier(RSOA) colorless transmitter are employed and no dispersion compensating fiber(DCF) is needed. Based on the bit error rate(BER) results of WDM signals, the proposed WDM-PON system can achieve up to 1.6 Tbit/s(100 Gbit/s/λ × 16 wavelengths) downstream transmission over a 30 km single mode fiber(SMF).展开更多
Based on the artificial intelligence algorithm of RetinaNet,we propose the Ghost-RetinaNet in this paper,a fast shadow detection method for photovoltaic panels,to solve the problems of extreme target density,large ove...Based on the artificial intelligence algorithm of RetinaNet,we propose the Ghost-RetinaNet in this paper,a fast shadow detection method for photovoltaic panels,to solve the problems of extreme target density,large overlap,high cost and poor real-time performance in photovoltaic panel shadow detection.Firstly,the Ghost CSP module based on Cross Stage Partial(CSP)is adopted in feature extraction network to improve the accuracy and detection speed.Based on extracted features,recursive feature fusion structure ismentioned to enhance the feature information of all objects.We introduce the SiLU activation function and CIoU Loss to increase the learning and generalization ability of the network and improve the positioning accuracy of the bounding box regression,respectively.Finally,in order to achieve fast detection,the Ghost strategy is chosen to lighten the size of the algorithm.The results of the experiment show that the average detection accuracy(mAP)of the algorithm can reach up to 97.17%,the model size is only 8.75 MB and the detection speed is highly up to 50.8 Frame per second(FPS),which can meet the requirements of real-time detection speed and accuracy of photovoltaic panels in the practical environment.The realization of the algorithm also provides new research methods and ideas for fault detection in the photovoltaic power generation system.展开更多
We experimentally demonstrate the transmission of discrete multi-tone(DMT)millimeter-wave(mm-wave)signals over a 1.2-km distance at the D-band(110–170 GHz)in a cost-effective intensity-modulation and direct-detection...We experimentally demonstrate the transmission of discrete multi-tone(DMT)millimeter-wave(mm-wave)signals over a 1.2-km distance at the D-band(110–170 GHz)in a cost-effective intensity-modulation and direct-detection(IM/DD)communication system.In the experiment,we successfully achieve the transmission of DMT-QPSK and DMT-16QAM mm-wave signals over multiple-input multiple-output(MIMO)links.After the 1.2-km free-space transmission,the bit error rate(BER)of the DMT-16QAM is below the 25%soft decision forward error correction(25%SD-FEC)threshold of 4×10^(-2),with a maximum net bit rate of 24.62 Gbit/s achieved in this system.展开更多
An adaptive dispersion estimation(ADE)is proposed to compensate dispersion and estimate the transfer function of the fiber channel with GerchbergSaxton(G-S)algorithm,using the stochastic gradient descent(SGD)method in...An adaptive dispersion estimation(ADE)is proposed to compensate dispersion and estimate the transfer function of the fiber channel with GerchbergSaxton(G-S)algorithm,using the stochastic gradient descent(SGD)method in the intensity-modulation and direct-detection(IM-DD)system,improving the tolerance of the algorithm to chromatic dispersion(CD).In order to address the divergence arising from the perturbation in the amplitude of the received signal caused by the filtering effect of the non-ideal channels,a channel-compensation equalizer(CCE)derived from the back-to-back(BTB)scenario is employed at the transmitter to make the amplitude of the received signal depicting the CD effect more accurately.The simulation results demonstrate the essentiality of CCE for the convergence and performance improvement of the G-S algorithm.Results show that it supports 112Gb/s four-level pulse amplitude modulation(PAM4)over 100 km standard single-mode fiber(SSMF)transmission under the 7%forward error correction(FEC)threshold of 3.8E-3.Besides,ADE improves the tolerance to wavelength drift from about 4 nm to 42 nm,and there is a better tolerance for fiber distance perturbation,indicating the G-S algorithm and its derived algorithms with the ADE scheme exhibit superior robustness to the perturbation in the system.展开更多
High resolution of surface plasmon resonance (SPR) detection is of vital importance.SPR biosensing system resolution is determined by intrinsic sensitivity of biochip and light signal acquisition system.In this articl...High resolution of surface plasmon resonance (SPR) detection is of vital importance.SPR biosensing system resolution is determined by intrinsic sensitivity of biochip and light signal acquisition system.In this article,different signal acquisition system resolutions on photodetector were analyzed based on light intensity and phase detection.Result shows that charge coupled device (CCD) with larger numbers of pixels is potential to achieve higher detection resolution.A 64 pixel line array CCD and a 12 bit ADC can achieve resolution of 10^(-7) refractive index unit (RIU).In array detection mode,increasing of detection throughput is at the cost of decreasing system resolution.Simulation analysis indicates that,if noise is taken into account,phase modulation methods are capable of providing better noise reduction performance than intensity methods.展开更多
Highly sensitive sensors with extensive applications are extremely desired in the next-generation wearable electronics for human motion monitoring,human-machine interface and intelligent robotics,while singlefunctiona...Highly sensitive sensors with extensive applications are extremely desired in the next-generation wearable electronics for human motion monitoring,human-machine interface and intelligent robotics,while singlefunctional pressure sensors cannot fulfill the growing demands of modern technological advances.Herein,an all-fabric and multilayered piezoresistive sensor based on conductive metal-organic frame-work/layered double hydroxide(cMOF/LDH)hetero-nanoforest is demonstrated to achieve multiple applications including pulse detection,joint motion detection,sound detection and information transmission.Benefiting from the synergism of cMOF/LDH hetero-nanoforest and multilayered structure,the sensor exhibits a high sensitivity(1.61×10^(9)kPa^(−1))over a broad pressure range(0-100 kPa),a fast response/recovery time(71 ms/71 ms)and a low detection limit(18 Pa),as well as reliable dynamic stability(8000 cycles).It is gratifying to note that the introduction of cMOFs endows the sensor with the potential to detect the concentration of NH_(3)(1-100 ppm)and sunlight intensity(10-100 mW cm^(−2)).This work shows great potential in multifunctional sensing,which enlightens a strategy for advancing the development process of highly sensitive intelligent wearable devices.展开更多
A digital transmission system with 900 MHz bandwidth and over 40 dB linear dynamic range for high intensity pulsed radial detection is designed. The transient signals （with a subnanoseconds rising edge） from the det...A digital transmission system with 900 MHz bandwidth and over 40 dB linear dynamic range for high intensity pulsed radial detection is designed. The transient signals （with a subnanoseconds rising edge） from the detectors can be transmitted to diagnosing systems kilometers away with high fidelity. It can adapt to interference and a hostile detecting environment by using the intelligent functions of this system. The feasibility and reliability of this system is verified by system evaluation tests.展开更多
A general formula for the dispersion limit of single-mode-fiber IM/DD (Intensity Modulation /Direct Detection) systems is derived for arbitrary given normalized pulse width P, eye opening penalty X and source linewidt...A general formula for the dispersion limit of single-mode-fiber IM/DD (Intensity Modulation /Direct Detection) systems is derived for arbitrary given normalized pulse width P, eye opening penalty X and source linewidth enchancement factor α. From the comparison with published theoretical results, computer simulation and experimental data, its validity and convenience in system design and evaluation are shown. Using this simple and general formula, one can easily obtain the dispersion limit of various fiber types under different working conditions in IM/DD systems.展开更多
In this paper,we propose an EADO-OFDM(Enhanced Asymmetrically Clipped DC Biased Optical Orthogonal Frequency Division Multiplexing)method for IM/DD(Intensity-Modulated DirectDetection)optical systems,in which the AV-D...In this paper,we propose an EADO-OFDM(Enhanced Asymmetrically Clipped DC Biased Optical Orthogonal Frequency Division Multiplexing)method for IM/DD(Intensity-Modulated DirectDetection)optical systems,in which the AV-DCO-OFDM(Absolute Valued DC Biased Optical OFDM)symbols on the even subcarriers and ACO-OFDM(Asymmetrically Clipped Optical OFDM)symbols on the odd subcarriers are combined for simultaneous transmission.Moreover,we discuss the PDF(Probability Density Function)and electrical SNR(Signal to Noise Ratio)of the symbols,which are utilized to estimate the BER(Bit Error Ratio)performance and overall performance of EADO-OFDM.The Monte Carlo simulation results have validated the theoretical analysis and have also confirmed the EADO-OFDM is attractive considering the following benefits.Firstly,EADO-OFDM is more energy efficient compared to the power-efficient DCO-OFDM(DC Biased Optical OFDM),since the required DC bias is smaller when appropriate constellation size combinations are chosen.In addition,EADO-OFDM performs better than the conventional ADO-OFDM(Asymmetrically Clipped DC Biased Optical OFDM),because the absolute value operation causes no clipping distortion.展开更多
We propose a multi-tap look-up-table(LUT)-based error-tracking decision feedback equalizer with partial unrolling(ET-DFEPU)algorithm to improve log-likelihood ratio(LLR)quality with error propagation.We introduce an e...We propose a multi-tap look-up-table(LUT)-based error-tracking decision feedback equalizer with partial unrolling(ET-DFEPU)algorithm to improve log-likelihood ratio(LLR)quality with error propagation.We introduce an error-tracking model to obtain the probabilities of different error states,which are input into the decoder to obtain more accurate LLRs.We also use LUTs to reduce the computation complexity of ET-DFE-PU.Moreover,we adopt a low-complexity partially unrolled architecture to relax the feedback timing constraint.We conduct experiments to transmit 170-Gb/s 4-ary pulse amplitude modulation signal in intensity modulation and direct-detection system at C-band.The results show that the proposed method can achieve 3-d B receiver sensitivity improvement at the same post-forward error correction bit error ratio compared with the conventional DFE.展开更多
基金supported by the Erciyes University Scientific Research Projects Coordination Unit (No.FDK-2019-8750)。
文摘In this paper, we have evaluated a bidirectional wavelength division multiplexing passive optical network(WDM-PON) employing intensity modulated/direct detection optical orthogonal frequency division multiplexing(IM/DD-OFDM). The proposed system employs 100 Gbit/s 16 quadrature amplitude modulation(16-QAM) downstream and 5 Gbit/s on-off keying(OOK) upstream wavelengths, respectively. The proposed system is considered low-cost as non-coherent IM/DD OFDM technology and a simple reflective semiconductor optical amplifier(RSOA) colorless transmitter are employed and no dispersion compensating fiber(DCF) is needed. Based on the bit error rate(BER) results of WDM signals, the proposed WDM-PON system can achieve up to 1.6 Tbit/s(100 Gbit/s/λ × 16 wavelengths) downstream transmission over a 30 km single mode fiber(SMF).
基金supported by the National Natural Science Foundation of China(No.52074305)Henan Scientific and Technological Research Project(No.212102210005)Open Fund of Henan Engineering Laboratory for Photoelectric Sensing and Intelligent Measurement and Control(No.HELPSIMC-2020-00X).
文摘Based on the artificial intelligence algorithm of RetinaNet,we propose the Ghost-RetinaNet in this paper,a fast shadow detection method for photovoltaic panels,to solve the problems of extreme target density,large overlap,high cost and poor real-time performance in photovoltaic panel shadow detection.Firstly,the Ghost CSP module based on Cross Stage Partial(CSP)is adopted in feature extraction network to improve the accuracy and detection speed.Based on extracted features,recursive feature fusion structure ismentioned to enhance the feature information of all objects.We introduce the SiLU activation function and CIoU Loss to increase the learning and generalization ability of the network and improve the positioning accuracy of the bounding box regression,respectively.Finally,in order to achieve fast detection,the Ghost strategy is chosen to lighten the size of the algorithm.The results of the experiment show that the average detection accuracy(mAP)of the algorithm can reach up to 97.17%,the model size is only 8.75 MB and the detection speed is highly up to 50.8 Frame per second(FPS),which can meet the requirements of real-time detection speed and accuracy of photovoltaic panels in the practical environment.The realization of the algorithm also provides new research methods and ideas for fault detection in the photovoltaic power generation system.
基金supported by the National Key R&D Program of China(No.2023YFB2905600)the National Natural Science Foundation of China(Nos.61935005,62127802,62331004,62305067)the Key Project of Jiangsu Province of China(No.BE2023001-4)。
文摘We experimentally demonstrate the transmission of discrete multi-tone(DMT)millimeter-wave(mm-wave)signals over a 1.2-km distance at the D-band(110–170 GHz)in a cost-effective intensity-modulation and direct-detection(IM/DD)communication system.In the experiment,we successfully achieve the transmission of DMT-QPSK and DMT-16QAM mm-wave signals over multiple-input multiple-output(MIMO)links.After the 1.2-km free-space transmission,the bit error rate(BER)of the DMT-16QAM is below the 25%soft decision forward error correction(25%SD-FEC)threshold of 4×10^(-2),with a maximum net bit rate of 24.62 Gbit/s achieved in this system.
基金funded by the National Natural Science Foundation of China NSFC,U22A2005 and 62201033theYoung Elite Scientists Sponsorship Program of CIC 2021QNRC001。
文摘An adaptive dispersion estimation(ADE)is proposed to compensate dispersion and estimate the transfer function of the fiber channel with GerchbergSaxton(G-S)algorithm,using the stochastic gradient descent(SGD)method in the intensity-modulation and direct-detection(IM-DD)system,improving the tolerance of the algorithm to chromatic dispersion(CD).In order to address the divergence arising from the perturbation in the amplitude of the received signal caused by the filtering effect of the non-ideal channels,a channel-compensation equalizer(CCE)derived from the back-to-back(BTB)scenario is employed at the transmitter to make the amplitude of the received signal depicting the CD effect more accurately.The simulation results demonstrate the essentiality of CCE for the convergence and performance improvement of the G-S algorithm.Results show that it supports 112Gb/s four-level pulse amplitude modulation(PAM4)over 100 km standard single-mode fiber(SSMF)transmission under the 7%forward error correction(FEC)threshold of 3.8E-3.Besides,ADE improves the tolerance to wavelength drift from about 4 nm to 42 nm,and there is a better tolerance for fiber distance perturbation,indicating the G-S algorithm and its derived algorithms with the ADE scheme exhibit superior robustness to the perturbation in the system.
文摘High resolution of surface plasmon resonance (SPR) detection is of vital importance.SPR biosensing system resolution is determined by intrinsic sensitivity of biochip and light signal acquisition system.In this article,different signal acquisition system resolutions on photodetector were analyzed based on light intensity and phase detection.Result shows that charge coupled device (CCD) with larger numbers of pixels is potential to achieve higher detection resolution.A 64 pixel line array CCD and a 12 bit ADC can achieve resolution of 10^(-7) refractive index unit (RIU).In array detection mode,increasing of detection throughput is at the cost of decreasing system resolution.Simulation analysis indicates that,if noise is taken into account,phase modulation methods are capable of providing better noise reduction performance than intensity methods.
基金supported by the National Natural Science Foundation of China(Nos.52271209 and 51762013)the Key Project of Hebei Natural Science Foundation(No.E20202201030)+5 种基金the Beijing-Tianjin-Hebei Collaborative Innovation Community Construction Project(No.21344301D)the Second Batch of Young Talent of Hebei Province(Nos.70280016160250 and 70280011808)the Key Fund in Hebei Province Department of Education China(No.ZD2021014)the Central Government Guide Local Funding Projects for Scientific and Technological Development(Nos.216Z4404G and 206Z4402G)the Interdisciplinary Research Program of Natural Science of Hebei University(No.DXK202107)the Government Foundation of Clinical Medicine Talents Training Program of Hebei Province(No.361007).
文摘Highly sensitive sensors with extensive applications are extremely desired in the next-generation wearable electronics for human motion monitoring,human-machine interface and intelligent robotics,while singlefunctional pressure sensors cannot fulfill the growing demands of modern technological advances.Herein,an all-fabric and multilayered piezoresistive sensor based on conductive metal-organic frame-work/layered double hydroxide(cMOF/LDH)hetero-nanoforest is demonstrated to achieve multiple applications including pulse detection,joint motion detection,sound detection and information transmission.Benefiting from the synergism of cMOF/LDH hetero-nanoforest and multilayered structure,the sensor exhibits a high sensitivity(1.61×10^(9)kPa^(−1))over a broad pressure range(0-100 kPa),a fast response/recovery time(71 ms/71 ms)and a low detection limit(18 Pa),as well as reliable dynamic stability(8000 cycles).It is gratifying to note that the introduction of cMOFs endows the sensor with the potential to detect the concentration of NH_(3)(1-100 ppm)and sunlight intensity(10-100 mW cm^(−2)).This work shows great potential in multifunctional sensing,which enlightens a strategy for advancing the development process of highly sensitive intelligent wearable devices.
基金Supported by National High Technology Research and Development Program of China(2007AA01Z275 )
文摘A digital transmission system with 900 MHz bandwidth and over 40 dB linear dynamic range for high intensity pulsed radial detection is designed. The transient signals （with a subnanoseconds rising edge） from the detectors can be transmitted to diagnosing systems kilometers away with high fidelity. It can adapt to interference and a hostile detecting environment by using the intelligent functions of this system. The feasibility and reliability of this system is verified by system evaluation tests.
基金the High Technology Research and Development Programme of China
文摘A general formula for the dispersion limit of single-mode-fiber IM/DD (Intensity Modulation /Direct Detection) systems is derived for arbitrary given normalized pulse width P, eye opening penalty X and source linewidth enchancement factor α. From the comparison with published theoretical results, computer simulation and experimental data, its validity and convenience in system design and evaluation are shown. Using this simple and general formula, one can easily obtain the dispersion limit of various fiber types under different working conditions in IM/DD systems.
基金supported in part by National Key Basic Research Program of China(No.2013CB329200)in part by Shenzhen Subject Arrangements(No.JCYJ20160331184124954)+4 种基金in part by Shenzhen Peacock Plan(No.1108170036003286)in part by Guangdong Science and Technology Planning Project(No.2014B010120001)in part by Shenzhen Fundamental Research Project(No.JCYJ20150401112337177)in part by Shenzhen Visible Light Communication System Key Laboratory(No.ZDSYS20140512114229398)in part by EPSRC Funded Projects(EP/N004558/1,EP/N023862/1).
文摘In this paper,we propose an EADO-OFDM(Enhanced Asymmetrically Clipped DC Biased Optical Orthogonal Frequency Division Multiplexing)method for IM/DD(Intensity-Modulated DirectDetection)optical systems,in which the AV-DCO-OFDM(Absolute Valued DC Biased Optical OFDM)symbols on the even subcarriers and ACO-OFDM(Asymmetrically Clipped Optical OFDM)symbols on the odd subcarriers are combined for simultaneous transmission.Moreover,we discuss the PDF(Probability Density Function)and electrical SNR(Signal to Noise Ratio)of the symbols,which are utilized to estimate the BER(Bit Error Ratio)performance and overall performance of EADO-OFDM.The Monte Carlo simulation results have validated the theoretical analysis and have also confirmed the EADO-OFDM is attractive considering the following benefits.Firstly,EADO-OFDM is more energy efficient compared to the power-efficient DCO-OFDM(DC Biased Optical OFDM),since the required DC bias is smaller when appropriate constellation size combinations are chosen.In addition,EADO-OFDM performs better than the conventional ADO-OFDM(Asymmetrically Clipped DC Biased Optical OFDM),because the absolute value operation causes no clipping distortion.
基金supported by the National Natural Science Foundation of China(Nos.62301128 and U22A2086)the STCSM(No.SKLSFO2021-01)+1 种基金the Open Fund of IPOC(BUPT)(No.IPOC2020A011)the Fundamental Research Funds for the Central Universities(Nos.ZYGX2020ZB043 and ZYGX2019J008)。
文摘We propose a multi-tap look-up-table(LUT)-based error-tracking decision feedback equalizer with partial unrolling(ET-DFEPU)algorithm to improve log-likelihood ratio(LLR)quality with error propagation.We introduce an error-tracking model to obtain the probabilities of different error states,which are input into the decoder to obtain more accurate LLRs.We also use LUTs to reduce the computation complexity of ET-DFE-PU.Moreover,we adopt a low-complexity partially unrolled architecture to relax the feedback timing constraint.We conduct experiments to transmit 170-Gb/s 4-ary pulse amplitude modulation signal in intensity modulation and direct-detection system at C-band.The results show that the proposed method can achieve 3-d B receiver sensitivity improvement at the same post-forward error correction bit error ratio compared with the conventional DFE.
