The rapid development of low earth orbit(LEO)satellite communication networks imposes stringent bandwidth,cost,and power consumption requirements.Conventional intradyne detection(ID)architectures struggle with high Do...The rapid development of low earth orbit(LEO)satellite communication networks imposes stringent bandwidth,cost,and power consumption requirements.Conventional intradyne detection(ID)architectures struggle with high Doppler frequency shifts(DFSs),necessitating excessive sampling rates and complex digital signal processing(DSP),resulting in elevated power consumption.This study proposes an inter-satellite polarization division multiplexing self-homodyne detection(PDM-SHD)architecture that compensates for DFSs in the optical domain by co-transmitting a polarization-orthogonal carrier light.The proposed architecture could achieve Nyquist sampling and half-quantization noise,leading to a 53.9%reduction in analog-to-digital converter power consumption under 40 Gbps 16-QAM transmission with a 16 dB signal-to-noise ratio.By demodulating I∕Q axis signals independently with real-valued single-input single-output(SISO)processing,it requires only about 15%DSP complexity and achieves intensity-modulation and direct-detection comparable.SISO processing also has the potential to transmit I and Q components from separate devices or satellites,enabling a flexible satellite communication network.The results demonstrate that the proposed architecture achieves detection sensitivities of−40.8 dBm for 80 Gbps quadrature phase-shift keying transmission and−33.0 dBm for 160 Gbps 16-QAM transmission with Nyquist sampling,whereas the ID architecture can hardly work.The proposed architecture effectively balances satellite power constraints with DSP computational demands for high-speed mega-constellation communications.展开更多
Space communication for deep-space missions,inter-satellite data transfer and Earth monitoring requires high-speed data connectivity.The reach is fundamentally dictated by the available transmission power,the aperture...Space communication for deep-space missions,inter-satellite data transfer and Earth monitoring requires high-speed data connectivity.The reach is fundamentally dictated by the available transmission power,the aperture size,and the receiver sensitivity.A transition from radio-frequency links to optical links is now seriously being considered,as this greatly reduces the channel loss caused by diffraction.A widely studied approach uses power-efficient formats along with nanowire-based photon-counting receivers cooled to a few Kelvins operating at speeds below 1 Gb/s.However,to achieve the multi-Gb/s data rates that will be required in the future,systems relying on pre-amplified receivers together with advanced signal generation and processing techniques from fibre communications are also considered.The sensitivity of such systems is largely determined by the noise figure(NF)of the pre-amplifier,which is theoretically 3 dB for almost all amplifiers.Phase-sensitive optical amplifiers(PSAs)with their uniquely low NF of 0 dB promise to provide the best possible sensitivity for Gb/s-rate long-haul free-space links.Here,we demonstrate a novel approach using a PSA-based receiver in a free-space transmission experiment with an unprecedented bit-error-free,black-box sensitivity of 1 photon-per-information-bit(PPB)at an information rate of 10.5 Gb/s.The system adopts a simple modulation format(quadrature-phase-shift keying,QPSK),standard digital signal processing for signal recovery and forward-error correction and is straightforwardly scalable to higher data rates.展开更多
We present the design, fabrication, and characterization of a highly nonlinear few-mode fiber(HNL-FMF) with an intermodal nonlinear coefficient of 2.8 W · km-1, which to the best of our knowledge is the highest r...We present the design, fabrication, and characterization of a highly nonlinear few-mode fiber(HNL-FMF) with an intermodal nonlinear coefficient of 2.8 W · km-1, which to the best of our knowledge is the highest reported to date. The graded-index circular core fiber supports two mode groups(MGs) with six eigenmodes and is highly doped with germanium. This breaks the mode degeneracy within the higher-order MG, leading to different group velocities among corresponding eigenmodes. Thus, the HNL-FMF can support multiple intermodal four-wave mixing processes between the two MGs at the same time. In a proof-of-concept experiment, we demonstrate simultaneous intermodal wavelength conversions among three eigenmodes of the HNL-FMF over the C band.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.62401220,62205111,and 62225110)the Major Program(JD)of Hubei Province(Grant No.2023BAA001-1)the Key Research and Development Program of Hubei Province of China(Grant No.2025BAB007).
文摘The rapid development of low earth orbit(LEO)satellite communication networks imposes stringent bandwidth,cost,and power consumption requirements.Conventional intradyne detection(ID)architectures struggle with high Doppler frequency shifts(DFSs),necessitating excessive sampling rates and complex digital signal processing(DSP),resulting in elevated power consumption.This study proposes an inter-satellite polarization division multiplexing self-homodyne detection(PDM-SHD)architecture that compensates for DFSs in the optical domain by co-transmitting a polarization-orthogonal carrier light.The proposed architecture could achieve Nyquist sampling and half-quantization noise,leading to a 53.9%reduction in analog-to-digital converter power consumption under 40 Gbps 16-QAM transmission with a 16 dB signal-to-noise ratio.By demodulating I∕Q axis signals independently with real-valued single-input single-output(SISO)processing,it requires only about 15%DSP complexity and achieves intensity-modulation and direct-detection comparable.SISO processing also has the potential to transmit I and Q components from separate devices or satellites,enabling a flexible satellite communication network.The results demonstrate that the proposed architecture achieves detection sensitivities of−40.8 dBm for 80 Gbps quadrature phase-shift keying transmission and−33.0 dBm for 160 Gbps 16-QAM transmission with Nyquist sampling,whereas the ID architecture can hardly work.The proposed architecture effectively balances satellite power constraints with DSP computational demands for high-speed mega-constellation communications.
基金supported by the Swedish Research Council(grant VR-2015-00535)the European Research Council(project ERC-2018-PoC 813236)Open access funding provided by Chalmers University of Technology.
文摘Space communication for deep-space missions,inter-satellite data transfer and Earth monitoring requires high-speed data connectivity.The reach is fundamentally dictated by the available transmission power,the aperture size,and the receiver sensitivity.A transition from radio-frequency links to optical links is now seriously being considered,as this greatly reduces the channel loss caused by diffraction.A widely studied approach uses power-efficient formats along with nanowire-based photon-counting receivers cooled to a few Kelvins operating at speeds below 1 Gb/s.However,to achieve the multi-Gb/s data rates that will be required in the future,systems relying on pre-amplified receivers together with advanced signal generation and processing techniques from fibre communications are also considered.The sensitivity of such systems is largely determined by the noise figure(NF)of the pre-amplifier,which is theoretically 3 dB for almost all amplifiers.Phase-sensitive optical amplifiers(PSAs)with their uniquely low NF of 0 dB promise to provide the best possible sensitivity for Gb/s-rate long-haul free-space links.Here,we demonstrate a novel approach using a PSA-based receiver in a free-space transmission experiment with an unprecedented bit-error-free,black-box sensitivity of 1 photon-per-information-bit(PPB)at an information rate of 10.5 Gb/s.The system adopts a simple modulation format(quadrature-phase-shift keying,QPSK),standard digital signal processing for signal recovery and forward-error correction and is straightforwardly scalable to higher data rates.
基金National Key R&D Program of China(2018YFB1801002)National Natural Science Foundation of China(61711530043)+2 种基金Fundamental Research Funds for the Central Universities(2018JYCXJJ024)Swedish Research Council(VR)(2015-00535,2017-05157)Swedish Foundation for International Cooperation in Research and Higher Education(STINT)(CH2016-6754)
文摘We present the design, fabrication, and characterization of a highly nonlinear few-mode fiber(HNL-FMF) with an intermodal nonlinear coefficient of 2.8 W · km-1, which to the best of our knowledge is the highest reported to date. The graded-index circular core fiber supports two mode groups(MGs) with six eigenmodes and is highly doped with germanium. This breaks the mode degeneracy within the higher-order MG, leading to different group velocities among corresponding eigenmodes. Thus, the HNL-FMF can support multiple intermodal four-wave mixing processes between the two MGs at the same time. In a proof-of-concept experiment, we demonstrate simultaneous intermodal wavelength conversions among three eigenmodes of the HNL-FMF over the C band.
