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
The bulky footprint of near-infrared(NIR)spectrometers has been limiting their applications in portable and movable systems for probing molecular compositions and structures.Quantum dot(QD)computational spectrometers ...The bulky footprint of near-infrared(NIR)spectrometers has been limiting their applications in portable and movable systems for probing molecular compositions and structures.Quantum dot(QD)computational spectrometers are a promising strategy for miniaturized NIR spectrometers,whose performance is limited by the poor spectral encoding matrix and,ultimately,the poor quality of PbS QDs.Here,we show that the monodispersity and finely controlled absorption peak of PbS QDs are critical parameters affecting the spectral resolution and noise resistance.Thus,a facile synthesis of a series of monodisperse PbS QDs from a single batch is developed using cation exchange synthesis in a seeded-growth manner.All the as-synthesized PbS QDs have narrow size distributions of below 4%,and the peak intervals can be controlled to within 3 nm.Furthermore,stable PbS QD inks are prepared by considering the compatibility between QD ligands,solvents,and polymers.The PbS QD filter array is fabricated using a contact printing method,exhibiting supreme transmittance curves and a spectral encoding matrix.The filter array is coupled with an InGaAs image sensor to form the QD NIR computational spectrometer.Thanks to the high-quality PbS QDs,the QD spectrometer shows a high spectral resolution of 1.5 nm in a broad wavelength range of 900−1700 nm and excellent spectral reconstruction of narrow and broad spectra with fidelities of above 0.987.Additionally,the QD spectrometer is applied to distinguish materials and accurately measure the alcohol content of white wines,demonstrating the great potential for practical applications of QD NIR spectrometers.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 National Key Research and Development Program of China(No.2021YFA0715502)the National Natural Science Foundation of China(No.62475084)+2 种基金the Scientific Research Project of Wenzhou(No.G2023025)the Innovation Project of Optics Valley Laboratory(No.OVL2023ZD002)the Fund from Science,Technology and Innovation Commission of Shenzhen Municipality(No.GJHZ20220913143403007).
文摘The bulky footprint of near-infrared(NIR)spectrometers has been limiting their applications in portable and movable systems for probing molecular compositions and structures.Quantum dot(QD)computational spectrometers are a promising strategy for miniaturized NIR spectrometers,whose performance is limited by the poor spectral encoding matrix and,ultimately,the poor quality of PbS QDs.Here,we show that the monodispersity and finely controlled absorption peak of PbS QDs are critical parameters affecting the spectral resolution and noise resistance.Thus,a facile synthesis of a series of monodisperse PbS QDs from a single batch is developed using cation exchange synthesis in a seeded-growth manner.All the as-synthesized PbS QDs have narrow size distributions of below 4%,and the peak intervals can be controlled to within 3 nm.Furthermore,stable PbS QD inks are prepared by considering the compatibility between QD ligands,solvents,and polymers.The PbS QD filter array is fabricated using a contact printing method,exhibiting supreme transmittance curves and a spectral encoding matrix.The filter array is coupled with an InGaAs image sensor to form the QD NIR computational spectrometer.Thanks to the high-quality PbS QDs,the QD spectrometer shows a high spectral resolution of 1.5 nm in a broad wavelength range of 900−1700 nm and excellent spectral reconstruction of narrow and broad spectra with fidelities of above 0.987.Additionally,the QD spectrometer is applied to distinguish materials and accurately measure the alcohol content of white wines,demonstrating the great potential for practical applications of QD NIR spectrometers.
