Integrated optical delay lines have become imperative to meet the growing demand as large aperture antennas and high number of subarrays required for microwave beamforming,high-speed optical communication,and integrat...Integrated optical delay lines have become imperative to meet the growing demand as large aperture antennas and high number of subarrays required for microwave beamforming,high-speed optical communication,and integrated quantum photonics.It is very challenging to achieve large delay ranges,small footprints,and broad bandwidths simultaneously due to the strong trade-off between the propagation loss and the group refractive index of optical waveguides.In this paper,we propose and experimentally demonstrate multimode-enabled silicon photonic delay line for the first time,which breaks the delay-density limit of singlemode waveguide spirals,towards a broadband,mm^(2)-scale,and ultra-large time delay.By demonstrating low-loss-propagation possibilities for different polarizations and modes,we introduce a novel multimode delay unit by integrating the mode(de)multiplexers and the ultralowloss multimode waveguide spiral supporting the TE_(0),TE_(1),and TE_(2)modes propagating in parallel.The measured propagation losses for the TE_(0),TE_(1),and TE_(2)modes are 0.2 dB/cm,0.31 dB/cm,and 0.49 dB/cm,respectively.In this way,the highest line delay-density of 376.9 ps/cm and low delay loss of 0.004 dB/ps are achieved.Furthermore,we implement a 7-bit tunable multimode photonic delay line and experimentally demonstrate an ultra-large delay range of 12.7 ns with a delay resolution of 100 ps and within an ultra-compact footprint of 3.85mm^(2),enabling a delay density over 3299 ps/mm^(2),showing the largest delay range and the highest delay density among on-chip delay lines reported to date,to the best of our knowledge.展开更多
We demonstrate significantly improved performance of a microwave true time delay line based on an integrated optical frequency comb source. The broadband micro-comb(over 100 nm wide) features a record low free spectra...We demonstrate significantly improved performance of a microwave true time delay line based on an integrated optical frequency comb source. The broadband micro-comb(over 100 nm wide) features a record low free spectral range(FSR) of 49 GHz, resulting in an unprecedented record high channel number(81 over the C band)—the highest number of channels for an integrated comb source used for microwave signal processing. We theoretically analyze the performance of a phased array antenna and show that this large channel count results in a high angular resolution and wide beam-steering tunable range. This demonstrates the feasibility of our approach as a competitive solution toward implementing integrated photonic true time delays in radar and communications systems.展开更多
基金supported by National Natural Science Foundation of China(U23B2047,62321166651,62305294,62175214,and 92150302)Natural Science Foundation of Zhejiang Province(LD19F050001)+2 种基金Zhejiang Provincial Major Research and Development Program(2022C01103)Fundamental Research Funds for the Central Universities(226202400171)Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(2021R01001).
文摘Integrated optical delay lines have become imperative to meet the growing demand as large aperture antennas and high number of subarrays required for microwave beamforming,high-speed optical communication,and integrated quantum photonics.It is very challenging to achieve large delay ranges,small footprints,and broad bandwidths simultaneously due to the strong trade-off between the propagation loss and the group refractive index of optical waveguides.In this paper,we propose and experimentally demonstrate multimode-enabled silicon photonic delay line for the first time,which breaks the delay-density limit of singlemode waveguide spirals,towards a broadband,mm^(2)-scale,and ultra-large time delay.By demonstrating low-loss-propagation possibilities for different polarizations and modes,we introduce a novel multimode delay unit by integrating the mode(de)multiplexers and the ultralowloss multimode waveguide spiral supporting the TE_(0),TE_(1),and TE_(2)modes propagating in parallel.The measured propagation losses for the TE_(0),TE_(1),and TE_(2)modes are 0.2 dB/cm,0.31 dB/cm,and 0.49 dB/cm,respectively.In this way,the highest line delay-density of 376.9 ps/cm and low delay loss of 0.004 dB/ps are achieved.Furthermore,we implement a 7-bit tunable multimode photonic delay line and experimentally demonstrate an ultra-large delay range of 12.7 ns with a delay resolution of 100 ps and within an ultra-compact footprint of 3.85mm^(2),enabling a delay density over 3299 ps/mm^(2),showing the largest delay range and the highest delay density among on-chip delay lines reported to date,to the best of our knowledge.
基金Australian Research Council(ARC)Discovery Projects Program(DP150104327)Strategic,Discovery and Acceleration Grants Schemes of Natural Sciences and Engineering Research Council of Canada(NSERC)+4 种基金MESI PSR-SIIRI Initiative in QuebecCanada Research Chairs ProgramITMO Fellowship and Professorship Program of the Government of the Russian Federation(074-U 01)1000 Talents Sichuan Program in ChinaStrategic Priority Research Program of the Chinese Academy of Sciences(CAS)(XDB24030000)
文摘We demonstrate significantly improved performance of a microwave true time delay line based on an integrated optical frequency comb source. The broadband micro-comb(over 100 nm wide) features a record low free spectral range(FSR) of 49 GHz, resulting in an unprecedented record high channel number(81 over the C band)—the highest number of channels for an integrated comb source used for microwave signal processing. We theoretically analyze the performance of a phased array antenna and show that this large channel count results in a high angular resolution and wide beam-steering tunable range. This demonstrates the feasibility of our approach as a competitive solution toward implementing integrated photonic true time delays in radar and communications systems.
