High-speed physical key distribution is diligently pursued for secure communication.In this paper,we propose and experimentally demonstrate a scheme of high-speed key distribution using mode-shift keying chaos synchro...High-speed physical key distribution is diligently pursued for secure communication.In this paper,we propose and experimentally demonstrate a scheme of high-speed key distribution using mode-shift keying chaos synchronization between two multi-longitudinal-mode Fabry–Perot lasers commonly driven by a super-luminescent diode.Legitimate users dynamically select one of the longitudinal modes according to private control codes to achieve mode-shift keying chaos synchronization.The two remote chaotic light waveforms are quantized to generate two raw random bit streams,and then those bits corresponding to chaos synchronization are sifted as shared keys by comparing the control codes.In this method,the transition time,i.e.,the chaos synchronization recovery time is determined by the rising time of the control codes rather than the laser transition response time,so the key distribution rate is improved greatly.Our experiment achieved a 0.75-Gbit/s key distribution rate with a bit error rate of 3.8×10^(−3)over 160-km fiber transmission with dispersion compensation.The entropy rate of the laser chaos is evaluated as 16 Gbit/s,which determines the ultimate final key rate together with the key generation ratio.It is therefore believed that the method pays a way for Gbit/s physical key distribution.展开更多
Visible light communication based on light-emitting diodes(LEDs) has become a promising candidate by providing high data rates, low latency, and secure communication for underwater environments. In this paper,a self-d...Visible light communication based on light-emitting diodes(LEDs) has become a promising candidate by providing high data rates, low latency, and secure communication for underwater environments. In this paper,a self-designed common-anode GaN-based five-primary-color LED(RGBYC LED) on a Si substrate is proposed and fabricated. The design of a common anode is used to mitigate the saturation effect for a low-frequency component. Additionally, compared with commercially available LEDs that suffer from nonlinearity distortion,applying the designed LED can provide much better and broader linearity according to the measurement results.Therefore, the modulation depth and system performance can be further improved to implement a high-speed underwater visible light communication(UVLC) system. There is no nonlinearity compensation algorithm applied due to the good linearity of the proposed LED;thus, the offline digital signal processing is simplified. We experimentally demonstrate 14.81 Gbit/s 64 quadrature amplitude modulation(QAM)-discrete multitone(DMT)and 15.17 Gbit/s bit-loading-DMT transmissions through a 1.2-m-long underwater channel based on the proposed RGBYC LED with an intrasymbol frequency-domain averaging channel estimation and zero-forcing equalization.As far as we know, this is the highest data rate for an LED-based UVLC system.展开更多
We demonstrate the optical transmission of an 800 Gbit/s(4×200 Gbit/s)pulse amplitude modulation-4(PAM-4)signal and a 480 Gbit/s(4×120 Gbit/s)on–off-keying(OOK)signal by using a high-bandwidth(BW)silicon ph...We demonstrate the optical transmission of an 800 Gbit/s(4×200 Gbit/s)pulse amplitude modulation-4(PAM-4)signal and a 480 Gbit/s(4×120 Gbit/s)on–off-keying(OOK)signal by using a high-bandwidth(BW)silicon photonic(SiP)transmitter with the aid of digital signal processing(DSP).In this transmitter,a four-channel SiP modulator chip is co-packaged with a four-channel driver chip,with a measured 3 dB BW of 40 GHz.DSP is applied in both the transmitter and receiver sides for pre-/post-compensation and bit error rate(BER)calculation.Back-to-back(B2B)BERs of the PAM-4 signal and OOK signal are first measured for each channel of the transmitter with respect to a variety of data rates.Similar BER performance of four channels shows good uniformity of the transmitter between different channels.The BER penalty of the PAM-4 and OOK signals for 500 m and 1 km standard single-mode fiber(SSMF)transmission is then experimentally tested by using one channel of the transmitter.For a 200 Gbit/s PAM-4 signal,the BER is below the hard-decision forward error correction(HD-FEC)threshold for B2B and below the soft-decision FEC(SD-FEC)threshold after 1 km transmission.For a 120 Gbit/s OOK signal,the BER is below SD-FEC threshold for B2B.After 500 m and 1 km transmission,the data rate of the OOK signal shrinks to 119 Gbit/s and 118 Gbit/s with the SD-FEC threshold,respectively.Finally,the 800 Gbit/s PAM-4 signal with 1 km transmission is achieved with the BER of all four channels below the SD-FEC threshold.展开更多
Free-space optical(FSO)communication technologies constitute a solution to cope with the bandwidth demand of future satellite-ground networks.They may overcome the RF bottleneck and attain data rates in the order of T...Free-space optical(FSO)communication technologies constitute a solution to cope with the bandwidth demand of future satellite-ground networks.They may overcome the RF bottleneck and attain data rates in the order of Tbit/s with only a handful of ground stations.Here,we demonstrate single-carrier Tbit/s line-rate transmission over a free-space channel of 53.42 km between the Jungfraujoch mountain top(3700 m)in the Swiss Alps and the Zimmerwald Observatory(895 m)near the city of Bern,achieving net-rates of up to 0.94 Tbit/s.With this scenario a satellite-ground feeder link is mimicked under turbulent conditions.Despite adverse conditions high throughput was achieved by employing a full adaptive optics system to correct the distorted wavefront of the channel and by using polarization-multiplexed high-order complex modulation formats.It was found that adaptive optics does not distort the reception of coherent modulation formats.Also,we introduce constellation modulation–a new four-dimensional BPSK(4D-BPSK)modulation format as a technique to transmit high data rates under lowest SNR.This way we show 53 km FSO transmission of 13.3 Gbit/s and 210 Gbit/s with as little as 4.3 and 7.8 photons per bit,respectively,at a bit-error ratio of 1∙10−3.The experiments show that advanced coherent modulation coding in combination with full adaptive optical filtering are proper means to make next-generation Tbit/s satellite communications practical.展开更多
In this investigation,all-optical Toggle flip-flop event-driven memory is explored with data rate of 16 Gbit/s.Single mode optical fiber model is used as a nonlinear medium to generate the output set and reset pulses ...In this investigation,all-optical Toggle flip-flop event-driven memory is explored with data rate of 16 Gbit/s.Single mode optical fiber model is used as a nonlinear medium to generate the output set and reset pulses of a Toggle flip-flop,and the model is based on the bidirectional optical transmission principle,considering the fundamental effects of cross phase modulation and self-phase modulation with change in polarization state.The performance of a flip-flop is evaluated using truth table conditions and performance parameters such as Q factor,which is obtained as 380.92 d B for Q and 272.9 d B for■,and rising and falling times of 7.304 ps and 5.79 ps,respectively are obtained,which makes flip-flop design fast as compared to earlier design techniques.展开更多
基金This work was supported by the National Key R&D Program of China(2019YFB1803500)the National Natural Science Foundation of China(61822509,62035009,61731014,61671316,61805170)+2 种基金the Shanxi Talent Program(201805D211027)the Shanxi“1331 Project”Key Innovative Team,the Program for Top Young and Middle-aged Innovative Talents of Shanxithe Program for Guangdong Introducing Innovative and Entrepreneurial Teams.
文摘High-speed physical key distribution is diligently pursued for secure communication.In this paper,we propose and experimentally demonstrate a scheme of high-speed key distribution using mode-shift keying chaos synchronization between two multi-longitudinal-mode Fabry–Perot lasers commonly driven by a super-luminescent diode.Legitimate users dynamically select one of the longitudinal modes according to private control codes to achieve mode-shift keying chaos synchronization.The two remote chaotic light waveforms are quantized to generate two raw random bit streams,and then those bits corresponding to chaos synchronization are sifted as shared keys by comparing the control codes.In this method,the transition time,i.e.,the chaos synchronization recovery time is determined by the rising time of the control codes rather than the laser transition response time,so the key distribution rate is improved greatly.Our experiment achieved a 0.75-Gbit/s key distribution rate with a bit error rate of 3.8×10^(−3)over 160-km fiber transmission with dispersion compensation.The entropy rate of the laser chaos is evaluated as 16 Gbit/s,which determines the ultimate final key rate together with the key generation ratio.It is therefore believed that the method pays a way for Gbit/s physical key distribution.
基金National Natural Science Foundation of China(NSFC)(61571133)National Key Research and Development Program of China(2016YFB0400600)
文摘Visible light communication based on light-emitting diodes(LEDs) has become a promising candidate by providing high data rates, low latency, and secure communication for underwater environments. In this paper,a self-designed common-anode GaN-based five-primary-color LED(RGBYC LED) on a Si substrate is proposed and fabricated. The design of a common anode is used to mitigate the saturation effect for a low-frequency component. Additionally, compared with commercially available LEDs that suffer from nonlinearity distortion,applying the designed LED can provide much better and broader linearity according to the measurement results.Therefore, the modulation depth and system performance can be further improved to implement a high-speed underwater visible light communication(UVLC) system. There is no nonlinearity compensation algorithm applied due to the good linearity of the proposed LED;thus, the offline digital signal processing is simplified. We experimentally demonstrate 14.81 Gbit/s 64 quadrature amplitude modulation(QAM)-discrete multitone(DMT)and 15.17 Gbit/s bit-loading-DMT transmissions through a 1.2-m-long underwater channel based on the proposed RGBYC LED with an intrasymbol frequency-domain averaging channel estimation and zero-forcing equalization.As far as we know, this is the highest data rate for an LED-based UVLC system.
基金National Key Research and Development Programe of China(2019YFB2205201,2019YFB2205203)Hubei Technological Innovation Project(2019AAA054).
文摘We demonstrate the optical transmission of an 800 Gbit/s(4×200 Gbit/s)pulse amplitude modulation-4(PAM-4)signal and a 480 Gbit/s(4×120 Gbit/s)on–off-keying(OOK)signal by using a high-bandwidth(BW)silicon photonic(SiP)transmitter with the aid of digital signal processing(DSP).In this transmitter,a four-channel SiP modulator chip is co-packaged with a four-channel driver chip,with a measured 3 dB BW of 40 GHz.DSP is applied in both the transmitter and receiver sides for pre-/post-compensation and bit error rate(BER)calculation.Back-to-back(B2B)BERs of the PAM-4 signal and OOK signal are first measured for each channel of the transmitter with respect to a variety of data rates.Similar BER performance of four channels shows good uniformity of the transmitter between different channels.The BER penalty of the PAM-4 and OOK signals for 500 m and 1 km standard single-mode fiber(SSMF)transmission is then experimentally tested by using one channel of the transmitter.For a 200 Gbit/s PAM-4 signal,the BER is below the hard-decision forward error correction(HD-FEC)threshold for B2B and below the soft-decision FEC(SD-FEC)threshold after 1 km transmission.For a 120 Gbit/s OOK signal,the BER is below SD-FEC threshold for B2B.After 500 m and 1 km transmission,the data rate of the OOK signal shrinks to 119 Gbit/s and 118 Gbit/s with the SD-FEC threshold,respectively.Finally,the 800 Gbit/s PAM-4 signal with 1 km transmission is achieved with the BER of all four channels below the SD-FEC threshold.
基金The project is financed by the H2020 EU Project VERTIGO(Grant Nr.822030)。
文摘Free-space optical(FSO)communication technologies constitute a solution to cope with the bandwidth demand of future satellite-ground networks.They may overcome the RF bottleneck and attain data rates in the order of Tbit/s with only a handful of ground stations.Here,we demonstrate single-carrier Tbit/s line-rate transmission over a free-space channel of 53.42 km between the Jungfraujoch mountain top(3700 m)in the Swiss Alps and the Zimmerwald Observatory(895 m)near the city of Bern,achieving net-rates of up to 0.94 Tbit/s.With this scenario a satellite-ground feeder link is mimicked under turbulent conditions.Despite adverse conditions high throughput was achieved by employing a full adaptive optics system to correct the distorted wavefront of the channel and by using polarization-multiplexed high-order complex modulation formats.It was found that adaptive optics does not distort the reception of coherent modulation formats.Also,we introduce constellation modulation–a new four-dimensional BPSK(4D-BPSK)modulation format as a technique to transmit high data rates under lowest SNR.This way we show 53 km FSO transmission of 13.3 Gbit/s and 210 Gbit/s with as little as 4.3 and 7.8 photons per bit,respectively,at a bit-error ratio of 1∙10−3.The experiments show that advanced coherent modulation coding in combination with full adaptive optical filtering are proper means to make next-generation Tbit/s satellite communications practical.
基金supported by the Science and Engineering Research Board,New Delhi for Research Grant Vide Sanction No:File No.EMR/2017/004162 dated 01-11-18。
文摘In this investigation,all-optical Toggle flip-flop event-driven memory is explored with data rate of 16 Gbit/s.Single mode optical fiber model is used as a nonlinear medium to generate the output set and reset pulses of a Toggle flip-flop,and the model is based on the bidirectional optical transmission principle,considering the fundamental effects of cross phase modulation and self-phase modulation with change in polarization state.The performance of a flip-flop is evaluated using truth table conditions and performance parameters such as Q factor,which is obtained as 380.92 d B for Q and 272.9 d B for■,and rising and falling times of 7.304 ps and 5.79 ps,respectively are obtained,which makes flip-flop design fast as compared to earlier design techniques.
