The mode hopping phenomenon induced by optical feedback in single-mode microchip Nd：YAG lasers is presented. With optical feedback, mode hopping strongly depends on two factors： the ratio of external cavity length t...The mode hopping phenomenon induced by optical feedback in single-mode microchip Nd：YAG lasers is presented. With optical feedback, mode hopping strongly depends on two factors： the ratio of external cavity length to intra-cavity length, and initial gains of the two hopping modes, When external cavity length equals an integral multiple of intracavity length, there is almost no mode hopping. However, if the external cavity length does not equal an integral multiple of intra-cavity length, mode hopping occurs. The ratio of external cavity length to intra-cavity length determines the position of two-mode hopping, The initial gains of the two hopping modes determine the corresponding peak values and oscillating periods of them in the intensity modulation curves.展开更多
We perform a theoretical study on the polarization-resolved compound lasing mode （CLM） of two mutually coupled vertical-cavity surface-emitting lasers （VCSELs）. Different solutions of CLMs are derived though stabi...We perform a theoretical study on the polarization-resolved compound lasing mode （CLM） of two mutually coupled vertical-cavity surface-emitting lasers （VCSELs）. Different solutions of CLMs are derived though stability analysis of the spin-flip model. The dynamical evolvements of CLMs with the existence of polarization degrees of freedom are also charactered. The most stable CLM with the smallest carrier density tend to be excited, since the gain needed for this mode to emit is the lowest. In the given system, varying values of injection rate or birefringence, etc., will change the generation of the preferred CLMs in the two polarization directions, and thus influence the polarization switching （PS） characteristics. Thus, hoppings between CLMs are also companied by PSs. Through mapping of average power in the parameter space, the influences of coupling rate and anisotropy parameters （linear dichroism and linear birefringence） on PS and hopping between CLMs are discussed.展开更多
This paper presents a wavelength-stepped swept laser based on a dispersion-tuned swept laser with the integration of a Mach-Zehnder interferometer,enabling a transition from continuous wavelength sweeping to wavelengt...This paper presents a wavelength-stepped swept laser based on a dispersion-tuned swept laser with the integration of a Mach-Zehnder interferometer,enabling a transition from continuous wavelength sweeping to wavelengthstepped sweeping.A comprehensive investigation of this laser is conducted,wherein different modulation schemes are employed to dynamically compare the switching mode,static-sweeping mode,and sweeping mode;the absence of mode hopping in the sweeping mode of the laser is verified.However,it is observed during experiments that the wavelength always remains stationary for a long time during the initiation of sweeping and change in sweeping direction,exhibiting latency compared to the modulation frequency variations.Through a simplistic modeling analysis of the composite cavity,it is revealed that the detuned state of the sub-cavity plays a critical role in the stable operation of the laser.Subsequently,simulation verification using the Ginzburg-Landau equation supports this observation.Additionally,compared to dispersion-tuned swept lasers,not only the linewidth significantly is narrowed in the proposed laser,but it also demonstrates enhanced stability during the sweeping process.This study provides,to our knowledge,a new laser source for ultra-fast optical imaging,ranging,and sensing applications,and presents novel methods and theoretical models for linewidth compression in swept lasers.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No 60438010）.
文摘The mode hopping phenomenon induced by optical feedback in single-mode microchip Nd：YAG lasers is presented. With optical feedback, mode hopping strongly depends on two factors： the ratio of external cavity length to intra-cavity length, and initial gains of the two hopping modes, When external cavity length equals an integral multiple of intracavity length, there is almost no mode hopping. However, if the external cavity length does not equal an integral multiple of intra-cavity length, mode hopping occurs. The ratio of external cavity length to intra-cavity length determines the position of two-mode hopping, The initial gains of the two hopping modes determine the corresponding peak values and oscillating periods of them in the intensity modulation curves.
基金the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20070613058)the Foundation for Key Program of the Ministry of Education, China (Grant No. 105148)and the Doctoral Innovation Fund of Southwest Jiaotong University
文摘We perform a theoretical study on the polarization-resolved compound lasing mode （CLM） of two mutually coupled vertical-cavity surface-emitting lasers （VCSELs）. Different solutions of CLMs are derived though stability analysis of the spin-flip model. The dynamical evolvements of CLMs with the existence of polarization degrees of freedom are also charactered. The most stable CLM with the smallest carrier density tend to be excited, since the gain needed for this mode to emit is the lowest. In the given system, varying values of injection rate or birefringence, etc., will change the generation of the preferred CLMs in the two polarization directions, and thus influence the polarization switching （PS） characteristics. Thus, hoppings between CLMs are also companied by PSs. Through mapping of average power in the parameter space, the influences of coupling rate and anisotropy parameters （linear dichroism and linear birefringence） on PS and hopping between CLMs are discussed.
基金National Key Research and Development Program of China(2023YFF0715700)Fundamental Research Funds for the Central Universities(2023CDJKYJH064)Chongqing Talents:Exceptional Young Talents Project(CQYC202005011)。
文摘This paper presents a wavelength-stepped swept laser based on a dispersion-tuned swept laser with the integration of a Mach-Zehnder interferometer,enabling a transition from continuous wavelength sweeping to wavelengthstepped sweeping.A comprehensive investigation of this laser is conducted,wherein different modulation schemes are employed to dynamically compare the switching mode,static-sweeping mode,and sweeping mode;the absence of mode hopping in the sweeping mode of the laser is verified.However,it is observed during experiments that the wavelength always remains stationary for a long time during the initiation of sweeping and change in sweeping direction,exhibiting latency compared to the modulation frequency variations.Through a simplistic modeling analysis of the composite cavity,it is revealed that the detuned state of the sub-cavity plays a critical role in the stable operation of the laser.Subsequently,simulation verification using the Ginzburg-Landau equation supports this observation.Additionally,compared to dispersion-tuned swept lasers,not only the linewidth significantly is narrowed in the proposed laser,but it also demonstrates enhanced stability during the sweeping process.This study provides,to our knowledge,a new laser source for ultra-fast optical imaging,ranging,and sensing applications,and presents novel methods and theoretical models for linewidth compression in swept lasers.
