The sweep rate,sweep range,and coherence length of swept sources,respectively,determine the acquisition rate,axial resolution,and imaging range of optical coherence tomography(OCT).In this paper,we demonstrate a recon...The sweep rate,sweep range,and coherence length of swept sources,respectively,determine the acquisition rate,axial resolution,and imaging range of optical coherence tomography(OCT).In this paper,we demonstrate a reconfigurable high-speed and broadband swept laser by time stretching of a flat spectrum femtosecond pulse train with over 100 nm bandwidth and a repetition rate of 100 MHz.By incorporating an optical modulator and utilizing appropriate dispersive modules,the reconfiguration of the swept source is demonstrated with sweep rates of 25 and 2.5 MHz.The 2.5 MHz swept source enables an imaging range of>110 mm with 6 dB sensitivity rolloff in OCT,which is the longest imaging range ever reported for megahertz OCT.展开更多
The increasing amount of data exchange requires higher-capacity optical communication links.Mode division multiplexing(MDM)is considered as a promising technology to support the higher data throughput.In an MDM system...The increasing amount of data exchange requires higher-capacity optical communication links.Mode division multiplexing(MDM)is considered as a promising technology to support the higher data throughput.In an MDM system,the mode generator and sorter are the backbone.However,most of the current schemes lack the programmability and universality,which makes the MDM link susceptible to the mode crosstalk and environmental disturbances.In this paper,we propose an intelligent multimode optical communication link using universal mode processing(generation and sorting)chips.The mode processor consists of a programmable 4×4 Mach Zehnder interferometer(MZI)network and can be intelligently configured to generate or sort both quasi linearly polarized(LP)modes and orbital angular momentum(OAM)modes in any desired routing state.We experimentally establish a chip-to-chip MDM communication system.The mode basis can be freely switched between four LP modes and four OAM modes.We also demonstrate the multimode optical communication capability at a data rate of 25 Gbit/s.The proposed scheme shows significant advantages in terms of universality,intelligence,programmability and resistance to mode crosstalk,environmental disturbances,and fabrication errors,demonstrating that the MZI-based reconfigurable mode processor chip has great potential in longdistance chip-to-chip multimode optical communication systems.展开更多
Frequency comb swept lasers are the enabling technology of circular interferometric imaging.which was proposed to break the bottleneck of data acquisition and proessing in optical coherence tomography(OCT)at video rat...Frequency comb swept lasers are the enabling technology of circular interferometric imaging.which was proposed to break the bottleneck of data acquisition and proessing in optical coherence tomography(OCT)at video rate.In this paper,we propose and demonstrate a highly coherent frequency comb swept laser by using a high-quality(high-Q)microring comb filter to discretize a Fourier domain mode-locked(FDML)laser.The microring filter has a Q factor of^2×10^6 and a linewidth of^90 MHz.To demonstrate the improvement in performance,a Fabry-Perot comb filter with a Q factor of 6.2×10^4 and a linewidth of 3.1 GHz is also used in the experiment for comparison.Both comb filters have free spectral ranges(FSRs)of^50 GHz for consistence.Stable and clearly discretized temporal waveforms and frequency comb spectra with 50 GHz FSR are observed.Adoption of the high-Q microring filter narrows the instantaneous linewidth of the FDML laser down to 1.5 GHz.The OCT system with the frequency comb swept laser source with a microring filter demonstrates an ultralong imaging range,which has a 6,10,and 15 dB sensitivity roll-off length of^53,~73,and over 100 mm,respectively.展开更多
基金National Key Research and Development Program of China(2019YFB1803900)Science,Technology and Innovation Commission of Shenzhen Municipality(SGDX2019081623060558)+1 种基金Research Grants Council,University Grants Committee of Hong Kong SAR(PolyU152241/18E,PolyU152471/16E)The Hong Kong Polytechnic University(1-BBAJ,1-ZVGB).
文摘The sweep rate,sweep range,and coherence length of swept sources,respectively,determine the acquisition rate,axial resolution,and imaging range of optical coherence tomography(OCT).In this paper,we demonstrate a reconfigurable high-speed and broadband swept laser by time stretching of a flat spectrum femtosecond pulse train with over 100 nm bandwidth and a repetition rate of 100 MHz.By incorporating an optical modulator and utilizing appropriate dispersive modules,the reconfiguration of the swept source is demonstrated with sweep rates of 25 and 2.5 MHz.The 2.5 MHz swept source enables an imaging range of>110 mm with 6 dB sensitivity rolloff in OCT,which is the longest imaging range ever reported for megahertz OCT.
基金National Natural Science Foundation of China(62275088,62075075,U21A20511)Innovation Project of Optics Valley Laboratory(Grant No.OVL2021BG001)+1 种基金Research Grants Council,University Grants Committee of Hong Kong SAR under Grant PolyU15301022Knowledge Innovation Program of Wuhan-Basic Research 2023010201010049.
文摘The increasing amount of data exchange requires higher-capacity optical communication links.Mode division multiplexing(MDM)is considered as a promising technology to support the higher data throughput.In an MDM system,the mode generator and sorter are the backbone.However,most of the current schemes lack the programmability and universality,which makes the MDM link susceptible to the mode crosstalk and environmental disturbances.In this paper,we propose an intelligent multimode optical communication link using universal mode processing(generation and sorting)chips.The mode processor consists of a programmable 4×4 Mach Zehnder interferometer(MZI)network and can be intelligently configured to generate or sort both quasi linearly polarized(LP)modes and orbital angular momentum(OAM)modes in any desired routing state.We experimentally establish a chip-to-chip MDM communication system.The mode basis can be freely switched between four LP modes and four OAM modes.We also demonstrate the multimode optical communication capability at a data rate of 25 Gbit/s.The proposed scheme shows significant advantages in terms of universality,intelligence,programmability and resistance to mode crosstalk,environmental disturbances,and fabrication errors,demonstrating that the MZI-based reconfigurable mode processor chip has great potential in longdistance chip-to-chip multimode optical communication systems.
基金Research Grants Council,University Grants Committee of Hong Kong SAR(PolyU152241/18E,PolyU152471/16E)Science,Technology and Innovation Commission of Shenzhen Municipality(JCYJ20160331141313917,SGDX2019081623060558)The Hong Kong Polytechnic University(1-BBAJ,1-ZVGB).
文摘Frequency comb swept lasers are the enabling technology of circular interferometric imaging.which was proposed to break the bottleneck of data acquisition and proessing in optical coherence tomography(OCT)at video rate.In this paper,we propose and demonstrate a highly coherent frequency comb swept laser by using a high-quality(high-Q)microring comb filter to discretize a Fourier domain mode-locked(FDML)laser.The microring filter has a Q factor of^2×10^6 and a linewidth of^90 MHz.To demonstrate the improvement in performance,a Fabry-Perot comb filter with a Q factor of 6.2×10^4 and a linewidth of 3.1 GHz is also used in the experiment for comparison.Both comb filters have free spectral ranges(FSRs)of^50 GHz for consistence.Stable and clearly discretized temporal waveforms and frequency comb spectra with 50 GHz FSR are observed.Adoption of the high-Q microring filter narrows the instantaneous linewidth of the FDML laser down to 1.5 GHz.The OCT system with the frequency comb swept laser source with a microring filter demonstrates an ultralong imaging range,which has a 6,10,and 15 dB sensitivity roll-off length of^53,~73,and over 100 mm,respectively.
