Optical frequency combs(OFCs)are highly promising candidates as multichannel light sources for photonic integrated circuits(PICs).We present a tunable on-chip OFC source based on quantum dot collidingpulse mode-locked...Optical frequency combs(OFCs)are highly promising candidates as multichannel light sources for photonic integrated circuits(PICs).We present a tunable on-chip OFC source based on quantum dot collidingpulse mode-locked lasers(QD-CPMLs),capable of generating both amplitude-modulated(AM)and frequencymodulated(FM)combs through external-cavity locking.A free-running fourth-order QD-CPML with a 100 GHz repetition rate is demonstrated to produce FM and AM combs under different bias conditions,achieving an ultra-wide comb with a 3-dB bandwidth of 1.8 THz and a 10-dB bandwidth of 2.5 THz.By leveraging externalcavity locking,the modulation dynamics of the comb are finely tuned,significantly expanding the AM comb range while reducing pulse width and chirp.The shortest pulse width achieved is 0.6 ps,with a minimum time-bandwidth product of 0.33,approaching the transform limit for hyperbolic secant pulses.The near-zero linewidth enhancement factor of the QD-CPML effectively suppresses coherence collapse under optical feedback,whereas its low group velocity dispersion facilitates the generation of narrow pulses and broad bandwidths.The ability to dynamically control AM and FM comb regions through external-cavity locking represents an innovative strategy for tunable OFC generation,offering potential for applications in sensing,spectroscopy,and optical communications within PICs.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB2803600)the National Natural Science Foundation of China(Grant Nos.62204072,62334013,and U22A2093)+3 种基金the Basic and Applied Basic Research Foundation of Guangdong Province(Grant Nos.2021A1515110076 and 2023A1515012304)the Shenzhen Science and Technology Innovation Program(Grant Nos.GXWD20220811163623002,RCBS20210609103824050,JCYJ20240813104819027,and KJZD20240903101100002)the Research Fund of the National Key Laboratory of Laser Spatial Information(Grant No.LSI2025WDZC03)the Open Research Program of the State Key Laboratory of Radio Frequency Heterogeneous Integration(Grant No.KF2025010).
文摘Optical frequency combs(OFCs)are highly promising candidates as multichannel light sources for photonic integrated circuits(PICs).We present a tunable on-chip OFC source based on quantum dot collidingpulse mode-locked lasers(QD-CPMLs),capable of generating both amplitude-modulated(AM)and frequencymodulated(FM)combs through external-cavity locking.A free-running fourth-order QD-CPML with a 100 GHz repetition rate is demonstrated to produce FM and AM combs under different bias conditions,achieving an ultra-wide comb with a 3-dB bandwidth of 1.8 THz and a 10-dB bandwidth of 2.5 THz.By leveraging externalcavity locking,the modulation dynamics of the comb are finely tuned,significantly expanding the AM comb range while reducing pulse width and chirp.The shortest pulse width achieved is 0.6 ps,with a minimum time-bandwidth product of 0.33,approaching the transform limit for hyperbolic secant pulses.The near-zero linewidth enhancement factor of the QD-CPML effectively suppresses coherence collapse under optical feedback,whereas its low group velocity dispersion facilitates the generation of narrow pulses and broad bandwidths.The ability to dynamically control AM and FM comb regions through external-cavity locking represents an innovative strategy for tunable OFC generation,offering potential for applications in sensing,spectroscopy,and optical communications within PICs.
