Facing escalating demands for high-speed,large-bandwidth,and low-latency wireless data links,laser communication technology has emerged as a promising technology.While free-space optical communication conventionally u...Facing escalating demands for high-speed,large-bandwidth,and low-latency wireless data links,laser communication technology has emerged as a promising technology.While free-space optical communication conventionally utilizes nearinfrared light sources,there has been growing interest in exploring new spectral resources,including visible lasers.Recently,laser-based white light has been demonstrated in visible light communication(VLC),with a unique capability to seamlessly integrate with illumination and display systems.This review summarizes the key devices and system technologies in semiconductor-laser-based white light for VLC-related applications.The recent advances and many emerging applications in the evolution of lighting,display,and communication are discussed.展开更多
Increasing bandwidth requirements have posed significant challenges for traditional access networks.It is difficult for intensity modulation/direct detection to meet the power budget and flexibility requirements of th...Increasing bandwidth requirements have posed significant challenges for traditional access networks.It is difficult for intensity modulation/direct detection to meet the power budget and flexibility requirements of the next-generation passive optical network(PON)at 100G and beyond considering the new requirements.This is driving researchers to develop novel optical access technologies.Low-cost,wide-coverage,and high-flexibility coherent PON is emerging as a strong contender in the competition.In this article,we will review technologies that reduce the complexity of coherent PON(CPON),enabling it to meet the commercial requirements.Also,advanced algorithms and architectures that can enhance system coverage and flexibility are also discussed.展开更多
This Letter proposes a post-equalizer for underwater visible light communication(UVLC) systems that combines channel estimation and joint time-frequency analysis, named channel-estimation-based bandpass variable-order...This Letter proposes a post-equalizer for underwater visible light communication(UVLC) systems that combines channel estimation and joint time-frequency analysis, named channel-estimation-based bandpass variable-order time-frequency network(CBV-TFNet). By utilizing a bandpass variable-order loss function with communication prior knowledge, CBVTFNet enhances communication performance and training stability. It enables lightweight implementation and faster convergence through a channel estimation-based mask. The superior performance of the proposed equalization method over Volterra and deep neural network(DNN)-based methods has been studied experimentally. Using bit-power loading discrete multitone (DMT) modulation, the proposed method achieves a transmission bitrate of 4.956 Gbps through a 1.2 m underwater channel utilizing only 38.15% of real multiplication calculations compared to the DNN equalizer and achieving a bitrate gain of440 Mbps and a significantly larger dynamic range over the LMS-Volterra equalizer. Results highlight CBV-TFNet's potential for future post-equalization in UVLC systems.展开更多
This paper experimentally demonstrates a distributed photonics-based W-band integrated sensing and communication(ISAC) system, in which radar sensing can aid the communication links in alignment and data rate estimati...This paper experimentally demonstrates a distributed photonics-based W-band integrated sensing and communication(ISAC) system, in which radar sensing can aid the communication links in alignment and data rate estimation. As a proof-of-concept, the ISAC system locates the users, guides the alignment, and sets a communication link with the estimated highest data rate. A peak net data rate of 68.6 Gbit/s and a target sensing with a less-than-1-cm error and a sub-2-cm resolution have been tested over a 10-km fiber and a 1.15-m free space transmission in the photonics-based W-band ISAC system. The achievable net data rates of the users at different locations estimated by sensing are experimentally verified.展开更多
In this Letter,we propose and experimentally demonstrate a lens-free wavefront shaping method that utilizes synchronized signal block beam alignment and a genetic algorithm(SSBGA)for a diffuse non-line-of-sight(NLOS)v...In this Letter,we propose and experimentally demonstrate a lens-free wavefront shaping method that utilizes synchronized signal block beam alignment and a genetic algorithm(SSBGA)for a diffuse non-line-of-sight(NLOS)visible light communication(VLC)system.The proposed method effectively controls the position and mobility of visible light beams by partitioning spatial light modulator pixels and manipulating beams to converge at distinct spatial positions,thereby enhancing wavefront shaping efficiency,which achieves a significant 23.9 dB optical power enhancement at+2 mm offset,surpassing the lens-based continuous sequence(CS)scheme by 21.7 dB.At+40°angle,the improvement reaches up to 11.8 dB and 16.8 dB compared to the results with and without lens-based CS,respectively.A maximum rate of 5.16 Gbps is successfully achieved using bit-power loading discrete multi-tone(DMT)modulation and the proposed SSBGA in an NLOS VLC system,which outperforms the lens-based CS by 1.07 Gbps and obtains a power saving of 55.6%during the transmission at4 Gbps.To the best of our knowledge,this is the first time that high-speed communication has been realized in an NLOS VLC system without a lens.展开更多
In this paper,we propose a 36-quadrature amplitude modulation(QAM)superposition modulation technique that is featured with uneven symbol probability by nonlinear precoding,named nonlinear coded nonuniform superpositio...In this paper,we propose a 36-quadrature amplitude modulation(QAM)superposition modulation technique that is featured with uneven symbol probability by nonlinear precoding,named nonlinear coded nonuniform superposition(NCNS)QAM.Its aim is to alleviate the nonlinearity effect caused by high instantaneous power in multi-input single-output(MISO)visible light communication(VLC)system,with an uneven probabilistic-shaped constellation.The transmitter includes two LEDs to send signals independently,and the receiver uses a photo detector to receive the superposed QAM signal.The experiment results show that NCNS has a better robustness against nonlinearity than pulse amplitude modulation 4,approximately gaining a 16% increase in maximum usable peak-to-peak voltage and a 33% enlargement in dynamic range area.It is a simple but effective approach to solve the bandwidth limits related to signal power and hopefully be applied in large power VLC systems such as underwater VLC,or to improve the robustness against power fluctuation.展开更多
We propose an encryption technique for underwater visible light communication[UVLC]based on chaotic phase scrambling[PS]and conjugate frequency hopping[CFH].The technique is experimentally tested using an 8-level puls...We propose an encryption technique for underwater visible light communication[UVLC]based on chaotic phase scrambling[PS]and conjugate frequency hopping[CFH].The technique is experimentally tested using an 8-level pulse amplitude modulation[PAM-8]and a 1.2 m underwater link.The security key of the phase scrambling code is generated according to a logistic map,and the frequency hopping is achieved by adding the same zero frequency points to the signal spectrum.The maximum transmission rate of 2.1 Gbit/s is measured with bit-error-rate[BER]below 7%the hard-decision forward error correction[HD-FEC]threshold of 3.8×10^(-3).展开更多
基金supported by the National Natural Science Foundation of China(Nos.62274042,61925104,and 62031011)the Natural Science Foundation of Shanghai(No.21ZR1406200)+1 种基金the Joint Project of China Mobile Research Institute&X-NET,Key Research and Development Program of Jiangsu Province(No.BE2021008-5)the King Abdullah University of Science and Technology(KAUST)(Nos.BAS/1/1614-01-01 and ORA-2022-5313).
文摘Facing escalating demands for high-speed,large-bandwidth,and low-latency wireless data links,laser communication technology has emerged as a promising technology.While free-space optical communication conventionally utilizes nearinfrared light sources,there has been growing interest in exploring new spectral resources,including visible lasers.Recently,laser-based white light has been demonstrated in visible light communication(VLC),with a unique capability to seamlessly integrate with illumination and display systems.This review summarizes the key devices and system technologies in semiconductor-laser-based white light for VLC-related applications.The recent advances and many emerging applications in the evolution of lighting,display,and communication are discussed.
基金supported in part by the National Key Research and Development Program of China(No.2023YFB2905700)in part by the National Natural Science Foundation of China(Nos.62171137,62235005,and 61925104)in part by the Natural Science Foundation of Shanghai(No.21ZR1408700)。
文摘Increasing bandwidth requirements have posed significant challenges for traditional access networks.It is difficult for intensity modulation/direct detection to meet the power budget and flexibility requirements of the next-generation passive optical network(PON)at 100G and beyond considering the new requirements.This is driving researchers to develop novel optical access technologies.Low-cost,wide-coverage,and high-flexibility coherent PON is emerging as a strong contender in the competition.In this article,we will review technologies that reduce the complexity of coherent PON(CPON),enabling it to meet the commercial requirements.Also,advanced algorithms and architectures that can enhance system coverage and flexibility are also discussed.
基金supported by the National Key Research and Development Program of China (No.2022YFB2802803)the National Natural Science Foundation of China (Nos.61925104,62031011,and 62201157)。
文摘This Letter proposes a post-equalizer for underwater visible light communication(UVLC) systems that combines channel estimation and joint time-frequency analysis, named channel-estimation-based bandpass variable-order time-frequency network(CBV-TFNet). By utilizing a bandpass variable-order loss function with communication prior knowledge, CBVTFNet enhances communication performance and training stability. It enables lightweight implementation and faster convergence through a channel estimation-based mask. The superior performance of the proposed equalization method over Volterra and deep neural network(DNN)-based methods has been studied experimentally. Using bit-power loading discrete multitone (DMT) modulation, the proposed method achieves a transmission bitrate of 4.956 Gbps through a 1.2 m underwater channel utilizing only 38.15% of real multiplication calculations compared to the DNN equalizer and achieving a bitrate gain of440 Mbps and a significantly larger dynamic range over the LMS-Volterra equalizer. Results highlight CBV-TFNet's potential for future post-equalization in UVLC systems.
基金supported by the National Key Research and Development Program of China (No.2022YFB2903600)the National Natural Science Foundation of China(Nos.62235005,62171137,61925104,62031011,and 62071444)the Major Key Project PCL。
文摘This paper experimentally demonstrates a distributed photonics-based W-band integrated sensing and communication(ISAC) system, in which radar sensing can aid the communication links in alignment and data rate estimation. As a proof-of-concept, the ISAC system locates the users, guides the alignment, and sets a communication link with the estimated highest data rate. A peak net data rate of 68.6 Gbit/s and a target sensing with a less-than-1-cm error and a sub-2-cm resolution have been tested over a 10-km fiber and a 1.15-m free space transmission in the photonics-based W-band ISAC system. The achievable net data rates of the users at different locations estimated by sensing are experimentally verified.
基金supported by the National Key Research and Development Program of China(No.2022YFB2802803)the National Natural Science Foundation of China(Nos.61925104,62031011,and 62201157)。
文摘In this Letter,we propose and experimentally demonstrate a lens-free wavefront shaping method that utilizes synchronized signal block beam alignment and a genetic algorithm(SSBGA)for a diffuse non-line-of-sight(NLOS)visible light communication(VLC)system.The proposed method effectively controls the position and mobility of visible light beams by partitioning spatial light modulator pixels and manipulating beams to converge at distinct spatial positions,thereby enhancing wavefront shaping efficiency,which achieves a significant 23.9 dB optical power enhancement at+2 mm offset,surpassing the lens-based continuous sequence(CS)scheme by 21.7 dB.At+40°angle,the improvement reaches up to 11.8 dB and 16.8 dB compared to the results with and without lens-based CS,respectively.A maximum rate of 5.16 Gbps is successfully achieved using bit-power loading discrete multi-tone(DMT)modulation and the proposed SSBGA in an NLOS VLC system,which outperforms the lens-based CS by 1.07 Gbps and obtains a power saving of 55.6%during the transmission at4 Gbps.To the best of our knowledge,this is the first time that high-speed communication has been realized in an NLOS VLC system without a lens.
基金This work was partially supported by the National Natural Science Foundation of China(Nos.61925104,62031011,and 62074072)China National Postdoctoral Program for Innovative Talents(No.BX2021082)+1 种基金China Postdoctoral Science Foundation(No.2021M700025)Major Key Project of PCL(No.PCL2021A14).
文摘In this paper,we propose a 36-quadrature amplitude modulation(QAM)superposition modulation technique that is featured with uneven symbol probability by nonlinear precoding,named nonlinear coded nonuniform superposition(NCNS)QAM.Its aim is to alleviate the nonlinearity effect caused by high instantaneous power in multi-input single-output(MISO)visible light communication(VLC)system,with an uneven probabilistic-shaped constellation.The transmitter includes two LEDs to send signals independently,and the receiver uses a photo detector to receive the superposed QAM signal.The experiment results show that NCNS has a better robustness against nonlinearity than pulse amplitude modulation 4,approximately gaining a 16% increase in maximum usable peak-to-peak voltage and a 33% enlargement in dynamic range area.It is a simple but effective approach to solve the bandwidth limits related to signal power and hopefully be applied in large power VLC systems such as underwater VLC,or to improve the robustness against power fluctuation.
基金supported by the National Key Research and Development Program of China(No.2022YFB2802803)the National Natural Science Foundation of China(Nos.61925104,62031011,and 62201157)the Major Key Project of PCL。
文摘We propose an encryption technique for underwater visible light communication[UVLC]based on chaotic phase scrambling[PS]and conjugate frequency hopping[CFH].The technique is experimentally tested using an 8-level pulse amplitude modulation[PAM-8]and a 1.2 m underwater link.The security key of the phase scrambling code is generated according to a logistic map,and the frequency hopping is achieved by adding the same zero frequency points to the signal spectrum.The maximum transmission rate of 2.1 Gbit/s is measured with bit-error-rate[BER]below 7%the hard-decision forward error correction[HD-FEC]threshold of 3.8×10^(-3).
