We investigate frequency-comb generation in normal dispersion silicon microresonators from the near-infrared to mid-infrared wavelength range in the presence of multiphoton absorption and free-carrier effects. It is f...We investigate frequency-comb generation in normal dispersion silicon microresonators from the near-infrared to mid-infrared wavelength range in the presence of multiphoton absorption and free-carrier effects. It is found that parametric oscillation is inhibited in the telecom wavelength range resulting from strong two-photon absorption.On the contrary, beyond the wavelength of 2200 nm, where three-and four-photon absorption are less detrimental,a comb can be generated with moderate pump power, or free-carriers are swept out by a positive-intrinsic-negative structure. In the temporal domain, the generated combs correspond to flat-top pulses, and the pulse duration can be easily controlled by varying the laser detuning. The reported comb generation process shows a high conversion efficiency compared with anomalous dispersion regime, which can guide and promote comb formation in materials with normal dispersion. As the comb spectra cover the mid-infrared wavelength range, they can find applications in comb-based radiofrequency photonic filters and mid-infrared spectroscopy.展开更多
A high-quality optical microcavity can enhance optical nonlinear effects by resonant recirculation,which provides a reliable platform for nonlinear optics research.When a soliton microcomb and a probe optical field ar...A high-quality optical microcavity can enhance optical nonlinear effects by resonant recirculation,which provides a reliable platform for nonlinear optics research.When a soliton microcomb and a probe optical field are coexisting in a micro-resonator,a concomitant microcomb(CMC)induced by cross-phase modulation(XPM)will be formed synchronously.Here,we characterize the CMC comprehensively in a micro-resonator through theory,numerical simulation,and experimental verification.It is found that the CMCs spectra are modulated due to resonant radiation(RR)resulting from the interaction of dispersion and XPM effects.The group velocity dispersion induces symmetric RRs on the CMC,which leads to a symmetric spectral envelope and a dual-peak pulse in frequency and temporal domains,respectively,while the group velocity mismatch breaks the symmetry of RRs and leads to asymmetric spectral and temporal profiles.When the group velocity is linearly varying with frequency,two RR frequencies are hyperbolically distributed about the pump,and the probe light acts as one of the asymptotic lines.Our results enrich the CMC dynamics and guide microcomb design and applications such as spectral extension and dark pulse generation.展开更多
Laser-based light detection and ranging(lidar)plays a significant role in both scientific and industrial areas.However,it is difficult for existing lidars to achieve high speed,high precision,and long distance simulta...Laser-based light detection and ranging(lidar)plays a significant role in both scientific and industrial areas.However,it is difficult for existing lidars to achieve high speed,high precision,and long distance simultaneously.Here,we demonstrate a high-performance lidar based on a chip-scaled soliton microcomb(SMC)that can realize all three specialties simultaneously.Aided by the excellent properties of ultrahigh repetition rate and the smooth envelope of the SMC,traditional optical frequency comb(OFC)-based dispersive interferometry is heavily improved and the measuring dead zone induced by the mismatch between the repetition rate of the OFC and resolution of the optical spectrum analyzer is totally eliminated.Combined with an auxiliary dual-frequency phase-modulated laser range finder,the none-dead-zone measurable range ambiguity is extended up to 1500 m.The proposed SMC lidar is experimentally implemented in both indoor and outdoor environment.In the outdoor baseline field,real-time,high-speed(up to 35 k Hz)measurement of a long distance of^1179 m is achieved with a minimum Allan deviation of 5.6μm at an average time of 0.2 ms(27 nm at an average time of 1.8 s after high-pass filtering).The present SMC lidar approaches a compact,fast,high-precision,and none-dead zone long-distance ranging system,aimed at emerging applications of frontier basic scientific research and advances in industrial manufacturing.展开更多
Soliton microcombs(SMCs)are spontaneously formed in a coherently pumped high-quality microresonator,which provides a new tool for use as an on-chip frequency comb for applications of high-precision metrology and spect...Soliton microcombs(SMCs)are spontaneously formed in a coherently pumped high-quality microresonator,which provides a new tool for use as an on-chip frequency comb for applications of high-precision metrology and spectroscopy.However,generation of SMCs seriously relies on advanced experimental techniques from professional scientists.Here,we experimentally demonstrate a program-controlled single SMC source where the intracavity thermal effect is timely balanced using an auxiliary laser during single SMC generation.The microcomb power is adopted as the criteria for microcomb states discrimination and a forward and backward thermal tuning technique is employed for the deterministic single SMC generation.Further,based on a closed-loop control system,the repetition rate stability of the SMC source improved more than 20 times and the pump frequency can be continuously tuned by simply changing the operation temperature.The reliability of the SMC source is verified by consecutive 200 generation trials and maintaining over 10 h.We believe the proposed SMC source will have significant promising influences in future SMC-based application development.展开更多
Dual combs are an emerging tool to obtain unprecedented resolution, high sensitivity, ultrahigh accuracy, broabandwidth, and ultrafast data updating rate in the fields of molecular spectroscopy, optical metrology, as ...Dual combs are an emerging tool to obtain unprecedented resolution, high sensitivity, ultrahigh accuracy, broabandwidth, and ultrafast data updating rate in the fields of molecular spectroscopy, optical metrology, as well optical frequency synthesis. The recent progress in chip-based microcombs has promoted the on-chip dual-commeasuring systems to a new phase attributed to the large frequency spacing and broad spectrum. In this paper, wdemonstrate proof-of-concept dual-comb generation with orthogonal polarization in a single microresonatthrough pumping both the transverse-electric(TE) and transverse-magnetic(TM) modes simultaneously. Ttwo orthogonal polarized pumps are self-oscillating in a fiber ring cavity. The generated dual comb exhibits ecellent stability due to the intrinsic feedback mechanism of the self-locked scheme. The repetition rate the two orthogonal combs is slightly different because of the mode spacing difference between the TE anTM modes. Such orthogonal polarized dual-combs could be a new comb source for out-of-lab applicatioin the fields of integrated spectroscopy, ranging measurement, optical frequency synthesis, and microwacomb generation.展开更多
基金National Natural Science Foundation of China(NSFC)(61635013,61675231,61475188,61705257)Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)(XDB24030600)
文摘We investigate frequency-comb generation in normal dispersion silicon microresonators from the near-infrared to mid-infrared wavelength range in the presence of multiphoton absorption and free-carrier effects. It is found that parametric oscillation is inhibited in the telecom wavelength range resulting from strong two-photon absorption.On the contrary, beyond the wavelength of 2200 nm, where three-and four-photon absorption are less detrimental,a comb can be generated with moderate pump power, or free-carriers are swept out by a positive-intrinsic-negative structure. In the temporal domain, the generated combs correspond to flat-top pulses, and the pulse duration can be easily controlled by varying the laser detuning. The reported comb generation process shows a high conversion efficiency compared with anomalous dispersion regime, which can guide and promote comb formation in materials with normal dispersion. As the comb spectra cover the mid-infrared wavelength range, they can find applications in comb-based radiofrequency photonic filters and mid-infrared spectroscopy.
基金National Key Research and Development Program of China(2021YFB2800603)National Natural Science Foundation of China(62075238)+1 种基金Foundation of Science and Technology on Metrology and Calibration Laboratory(JLJK2021001A004)West Light Foundation of the Chinese Academy of Sciences(E0291113)。
文摘A high-quality optical microcavity can enhance optical nonlinear effects by resonant recirculation,which provides a reliable platform for nonlinear optics research.When a soliton microcomb and a probe optical field are coexisting in a micro-resonator,a concomitant microcomb(CMC)induced by cross-phase modulation(XPM)will be formed synchronously.Here,we characterize the CMC comprehensively in a micro-resonator through theory,numerical simulation,and experimental verification.It is found that the CMCs spectra are modulated due to resonant radiation(RR)resulting from the interaction of dispersion and XPM effects.The group velocity dispersion induces symmetric RRs on the CMC,which leads to a symmetric spectral envelope and a dual-peak pulse in frequency and temporal domains,respectively,while the group velocity mismatch breaks the symmetry of RRs and leads to asymmetric spectral and temporal profiles.When the group velocity is linearly varying with frequency,two RR frequencies are hyperbolically distributed about the pump,and the probe light acts as one of the asymptotic lines.Our results enrich the CMC dynamics and guide microcomb design and applications such as spectral extension and dark pulse generation.
基金Key Projects Supported by Science and Technology of Tianjin(18YFZCGX00920)Youth Innovation Promotion Association of the Chinese Academy of Sciences(2016353)+2 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(XDB24030600)National Key Research and Development Program of China(2018YFB2003501,2018YFF0212702)National Natural Science Foundation of China(51675380,51775379,61635013,61675231,61705257,61805277)。
文摘Laser-based light detection and ranging(lidar)plays a significant role in both scientific and industrial areas.However,it is difficult for existing lidars to achieve high speed,high precision,and long distance simultaneously.Here,we demonstrate a high-performance lidar based on a chip-scaled soliton microcomb(SMC)that can realize all three specialties simultaneously.Aided by the excellent properties of ultrahigh repetition rate and the smooth envelope of the SMC,traditional optical frequency comb(OFC)-based dispersive interferometry is heavily improved and the measuring dead zone induced by the mismatch between the repetition rate of the OFC and resolution of the optical spectrum analyzer is totally eliminated.Combined with an auxiliary dual-frequency phase-modulated laser range finder,the none-dead-zone measurable range ambiguity is extended up to 1500 m.The proposed SMC lidar is experimentally implemented in both indoor and outdoor environment.In the outdoor baseline field,real-time,high-speed(up to 35 k Hz)measurement of a long distance of^1179 m is achieved with a minimum Allan deviation of 5.6μm at an average time of 0.2 ms(27 nm at an average time of 1.8 s after high-pass filtering).The present SMC lidar approaches a compact,fast,high-precision,and none-dead zone long-distance ranging system,aimed at emerging applications of frontier basic scientific research and advances in industrial manufacturing.
基金National Natural Science Foundation of China(61635013,61675231)National Key Research and Development Program of China(2019YFA0308200)Strategic Priority Research Program of the Chinese Academy of Sciences(XDB24030600)。
文摘Soliton microcombs(SMCs)are spontaneously formed in a coherently pumped high-quality microresonator,which provides a new tool for use as an on-chip frequency comb for applications of high-precision metrology and spectroscopy.However,generation of SMCs seriously relies on advanced experimental techniques from professional scientists.Here,we experimentally demonstrate a program-controlled single SMC source where the intracavity thermal effect is timely balanced using an auxiliary laser during single SMC generation.The microcomb power is adopted as the criteria for microcomb states discrimination and a forward and backward thermal tuning technique is employed for the deterministic single SMC generation.Further,based on a closed-loop control system,the repetition rate stability of the SMC source improved more than 20 times and the pump frequency can be continuously tuned by simply changing the operation temperature.The reliability of the SMC source is verified by consecutive 200 generation trials and maintaining over 10 h.We believe the proposed SMC source will have significant promising influences in future SMC-based application development.
基金National Natural Science Foundation of China(NSFC)(61475188,61605151,61635013,61675231)Strategic Priority Research Program,Chinese Academy of Sciences(CAS)(XDB24030600)
文摘Dual combs are an emerging tool to obtain unprecedented resolution, high sensitivity, ultrahigh accuracy, broabandwidth, and ultrafast data updating rate in the fields of molecular spectroscopy, optical metrology, as well optical frequency synthesis. The recent progress in chip-based microcombs has promoted the on-chip dual-commeasuring systems to a new phase attributed to the large frequency spacing and broad spectrum. In this paper, wdemonstrate proof-of-concept dual-comb generation with orthogonal polarization in a single microresonatthrough pumping both the transverse-electric(TE) and transverse-magnetic(TM) modes simultaneously. Ttwo orthogonal polarized pumps are self-oscillating in a fiber ring cavity. The generated dual comb exhibits ecellent stability due to the intrinsic feedback mechanism of the self-locked scheme. The repetition rate the two orthogonal combs is slightly different because of the mode spacing difference between the TE anTM modes. Such orthogonal polarized dual-combs could be a new comb source for out-of-lab applicatioin the fields of integrated spectroscopy, ranging measurement, optical frequency synthesis, and microwacomb generation.