We solve the single mode coupled rate equations by computer,simulate the behavior of a gain switch of an AlGaInP red light semiconductor laser diode,and find the characteristic of FWHM of pulses changing with the ampl...We solve the single mode coupled rate equations by computer,simulate the behavior of a gain switch of an AlGaInP red light semiconductor laser diode,and find the characteristic of FWHM of pulses changing with the amplitude of modulation signal, the bias current, and the modulated frequency. On this basis, we conduct experiments. The experiment results accord with the simulations well.展开更多
Electroluminescence (EL) and temperature-dependent photolumineseenee measurements are performed to study the internal quantum efficiency droop phenomenon of blue laser diodes (LDs) before lasing. Based on the ABC ...Electroluminescence (EL) and temperature-dependent photolumineseenee measurements are performed to study the internal quantum efficiency droop phenomenon of blue laser diodes (LDs) before lasing. Based on the ABC mode, the EL result demonstrates that non-radiative recombination rates of LDs with threshold current densities of 4 and 6kA/cm2 are similar, while LD with threshold current density of 4kA/cm2 exhibits a smaller auger- like recombination rate compared with the one of 6kA/cm2. The internal quantum efficiency droop is more serious for LD with higher threshold current density. temperature-dependent photoluminescence is consistent The internal quantum efficiency value estimated from with EL measurements.展开更多
An accurate technique for measuring the frequency response of semiconductor laser diode chips is proposed and experimentally demonstrated.The effects of test jig parasites can be completely removed in the measurement ...An accurate technique for measuring the frequency response of semiconductor laser diode chips is proposed and experimentally demonstrated.The effects of test jig parasites can be completely removed in the measurement by a new calibration method.In theory,the measuring range of the measurement system is only determined by the measuring range of the instruments network analyzer and photo detector.Diodes' bandwidth of 7 5GHz and 10GHz is measured.The results reveal that the method is feasible and comparing with other method,it is more precise and easier to use.展开更多
Light detection and ranging (LIDAR) based on time of flight (TOF) method is widely used in many fields related to distance measurement. LIDAR generally uses laser diode (LD) to emit the pulsed laser with high peak pow...Light detection and ranging (LIDAR) based on time of flight (TOF) method is widely used in many fields related to distance measurement. LIDAR generally uses laser diode (LD) to emit the pulsed laser with high peak power and short duration to ensure a large distance measurement range and eye safety. To achieve this goal, we propose a pulsed LD drive method producing the drive current with high peak and narrow pulse width. We analyze the key issues and related theories of the drive current generation based on this method and design an LD driver. A model of drive current generation is established and the influence of operating frequency on drive current is discussed. The LD driver is simulated by software and verified by experiments. The working frequency of the driver changes from 20 kHz to 100 kHz and the charging voltage is set at 130 V. The current produced by this driver has a duration of 8.8 ns and a peak of about 35 A, and the peak output optical power of the LD exceeds 75 W.展开更多
A tunable single-passband microwave photonic filter is proposed and demonstrated, based on a laser diode (LD) array with multiple optical carriers and a Fabry-Perot (F-P) laser diode. Multiple optical carriers in conj...A tunable single-passband microwave photonic filter is proposed and demonstrated, based on a laser diode (LD) array with multiple optical carriers and a Fabry-Perot (F-P) laser diode. Multiple optical carriers in conjunction with the F-P LD will realize a filter with multiple passbands. By adjusting the wavelengths of the multiple optical carriers, multiple passbands are merged into a single passband with a broadened bandwidth. By varying the number of the optical carrier, the bandwidth can be adjusted. The central frequency can be tuned by adjusting the wavelength of the multiple optical carriers simultaneously. A single-passband filter implemented by two optical carriers is experimentally demonstrated.展开更多
We report one thick layer of hard-baked photoresist mask.The laser array stripe pattern was defined by standard wet lithography.With this mask, a 10 W QCW(quasi-continuous wave) operation of a narrow proton implanted ...We report one thick layer of hard-baked photoresist mask.The laser array stripe pattern was defined by standard wet lithography.With this mask, a 10 W QCW(quasi-continuous wave) operation of a narrow proton implanted multiple stripe conventional single quantum well separate confinement heterostructure(SQW-SCH) GaAlAs diode laser array has been realized.These devices exhibit the lateral far-field radiation pattern of a phase-locked array of gain-guided semiconductor injection laser array.The twenty stripe laser array has a lateral far-field beam divergence full width at half maximum(FWHM) of less than 3°,and three twenty stripe laser array has a beam divergence in the plane of the junction of about 9°.展开更多
A fiber-coupled laser-diode (LD) end-pumped Nd:GdVO4 slab continuous-wave (CW) 912-nm laser and an LD bar end-pumped Nd:GdVO4 slab CW 912-nm laser are both demonstrated in this paper. Using the fiber-coupled LD ...A fiber-coupled laser-diode (LD) end-pumped Nd:GdVO4 slab continuous-wave (CW) 912-nm laser and an LD bar end-pumped Nd:GdVO4 slab CW 912-nm laser are both demonstrated in this paper. Using the fiber-coupled LD of end-pumped type, a highest CW 912-nm laser output power of 10.17 W is obtained with a high optical to-optical conversion efficiency of 24.6% and a slope efficiency of 34.5%. The measured M2 factors of beam quality in x and y directions are 5.3 and 5.1, respectively. Besides, an LD bar of end-pumped type is used to realize CW 912-nm laser output, which has the advantages of compactness and low cost. When the pump power is 38.8 W, the output power is 8.87 W and the measured M^2 factors of beam quality in x and y directions are 16 and 1.31, respectively. In order to improve the beam quality of the 912-nm laser at x direction, a new quasi-concentric laser resonator will be designed, and an LD bar end-pumped Nd:GdVO4 slab high-power CW 912-nm TEM00 laser will be realized in the future.展开更多
An overview of the applications of semiconductor lasers is presented. Diode lasers are widely used today, and the most prevalent use of the laser is probably in CD and DVD drives for computers and audio/video media sy...An overview of the applications of semiconductor lasers is presented. Diode lasers are widely used today, and the most prevalent use of the laser is probably in CD and DVD drives for computers and audio/video media sys- tems. Semiconductor lasers are also used in many other fields ranging from optical fiber communications to display, medicine and pumping sources.展开更多
目的利用Diode激光联合根面平整(scaling and root planning,SRP)治疗重度慢性牙周炎,并评价其疗效,以期为治疗重度慢性牙周炎提供可靠有效的方法。方法选择2018年1—12月在中国科技大学附属第一医院牙周科门诊收治重度牙周炎病人46例...目的利用Diode激光联合根面平整(scaling and root planning,SRP)治疗重度慢性牙周炎,并评价其疗效,以期为治疗重度慢性牙周炎提供可靠有效的方法。方法选择2018年1—12月在中国科技大学附属第一医院牙周科门诊收治重度牙周炎病人46例为研究对象,共252颗左右分布的同名患牙;所有受试牙进行全口超声龈上洁治后行牙周检查,结果作为基线水平,当日进行口腔卫生宣教。在基线水平上将同一病人的左右侧同名受试牙随机分组,一侧为激光联合SRP治疗组(观察组)46例126牙,1周后采用刮治器和激光进行治疗;另一侧即为单纯SRP组(对照组)46例126牙。在基线水平、治疗后第8、第12周对比两组间的牙周评价指标:牙周袋探诊深度(pocket probing depth,PPD)、临床附着水平丧失(clinical attachment loss,CAL)、龈沟出血指数(sulcus bleeding index,SBI)、探诊出血(bleeding on probing,BOP);结果观察组第8周、第12周PPD值分别为(3.17±0.45)mm,(2.95±0.41)mm;CAL值分别为(7.52±1.12)mm,(6.87±1.13)mm,和对照组同时点比较差异无统计学意义,然而两组与基线水平比较均差异有统计学意义(P<0.05)。观察组BOP值8周,12周分别为(15.85±14.81)%,(14.57±7.6)%,SBI值8周,12周分别为(1.14±0.28)°,(1.02±0.37)°;较基线水平明显改善,而且在观察组比对照组的改善程度更为明显,差异有统计学意义(P<0.05)。结论Diode激光联合根面平整(SRP)治疗重度慢性牙周炎较单独使用根面平整取得良好的短期效果,值得临床推广使用。展开更多
为了使半导体激光器的激光波长和输出功率稳定,必须对其温度进行控制。介绍了LD泵浦固体激光器恒温控制系统的软、硬件方面设计。温度采集电路采用具有高输入阻抗和高共模抑制比的测量放大电路,利用半导体制冷器(thermo electric cooler...为了使半导体激光器的激光波长和输出功率稳定,必须对其温度进行控制。介绍了LD泵浦固体激光器恒温控制系统的软、硬件方面设计。温度采集电路采用具有高输入阻抗和高共模抑制比的测量放大电路,利用半导体制冷器(thermo electric cooler,TEC)作为控温系统的控温执行器件。由改变驱动TEC电流的方向来实现制冷或者加热,软件采用增量型防积分饱和的数字PID算法,根据实验结果温控控制精度在±0.5℃,可以满足对半导体激光器温度控制精度和稳定性的要求。展开更多
文摘We solve the single mode coupled rate equations by computer,simulate the behavior of a gain switch of an AlGaInP red light semiconductor laser diode,and find the characteristic of FWHM of pulses changing with the amplitude of modulation signal, the bias current, and the modulated frequency. On this basis, we conduct experiments. The experiment results accord with the simulations well.
基金Supported by the National Key Research and Development Program of China under Grant Nos 2016YFB0401803 and 2016YFB0402002the National Natural Science Foundation of China under Grant Nos 61574160 and 61334005+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No XDA09020401the Visiting Professorship for Senior International Scientists of the Chinese Academy of Sciences under Grant No 2013T2J0048
文摘Electroluminescence (EL) and temperature-dependent photolumineseenee measurements are performed to study the internal quantum efficiency droop phenomenon of blue laser diodes (LDs) before lasing. Based on the ABC mode, the EL result demonstrates that non-radiative recombination rates of LDs with threshold current densities of 4 and 6kA/cm2 are similar, while LD with threshold current density of 4kA/cm2 exhibits a smaller auger- like recombination rate compared with the one of 6kA/cm2. The internal quantum efficiency droop is more serious for LD with higher threshold current density. temperature-dependent photoluminescence is consistent The internal quantum efficiency value estimated from with EL measurements.
文摘An accurate technique for measuring the frequency response of semiconductor laser diode chips is proposed and experimentally demonstrated.The effects of test jig parasites can be completely removed in the measurement by a new calibration method.In theory,the measuring range of the measurement system is only determined by the measuring range of the instruments network analyzer and photo detector.Diodes' bandwidth of 7 5GHz and 10GHz is measured.The results reveal that the method is feasible and comparing with other method,it is more precise and easier to use.
基金National Key Research and Development Plan(No.2017YFF0204800)Natural Science Foundation of Tianjin(No.17JCQNJC01100)+3 种基金National Natural Science Foundation of China(Nos.61501319,51775377,61505140)Young Elite Scientists Sponsorship Program by Cast of China(No.2016QNRC001)Open Project of Key Laboratory of Micro Opto-electro Mechanical System Technology(No.MOMST2015-7)Open Project from Photoelectric Information and Instrument-Engineering Research Center of Beijing,Tianjin University,Ministry of Education(No.GD2015007)
文摘Light detection and ranging (LIDAR) based on time of flight (TOF) method is widely used in many fields related to distance measurement. LIDAR generally uses laser diode (LD) to emit the pulsed laser with high peak power and short duration to ensure a large distance measurement range and eye safety. To achieve this goal, we propose a pulsed LD drive method producing the drive current with high peak and narrow pulse width. We analyze the key issues and related theories of the drive current generation based on this method and design an LD driver. A model of drive current generation is established and the influence of operating frequency on drive current is discussed. The LD driver is simulated by software and verified by experiments. The working frequency of the driver changes from 20 kHz to 100 kHz and the charging voltage is set at 130 V. The current produced by this driver has a duration of 8.8 ns and a peak of about 35 A, and the peak output optical power of the LD exceeds 75 W.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61302026,61275067 and 61575034the Jiangsu Natural Science Foundation under Grant No BK2012432
文摘A tunable single-passband microwave photonic filter is proposed and demonstrated, based on a laser diode (LD) array with multiple optical carriers and a Fabry-Perot (F-P) laser diode. Multiple optical carriers in conjunction with the F-P LD will realize a filter with multiple passbands. By adjusting the wavelengths of the multiple optical carriers, multiple passbands are merged into a single passband with a broadened bandwidth. By varying the number of the optical carrier, the bandwidth can be adjusted. The central frequency can be tuned by adjusting the wavelength of the multiple optical carriers simultaneously. A single-passband filter implemented by two optical carriers is experimentally demonstrated.
文摘We report one thick layer of hard-baked photoresist mask.The laser array stripe pattern was defined by standard wet lithography.With this mask, a 10 W QCW(quasi-continuous wave) operation of a narrow proton implanted multiple stripe conventional single quantum well separate confinement heterostructure(SQW-SCH) GaAlAs diode laser array has been realized.These devices exhibit the lateral far-field radiation pattern of a phase-locked array of gain-guided semiconductor injection laser array.The twenty stripe laser array has a lateral far-field beam divergence full width at half maximum(FWHM) of less than 3°,and three twenty stripe laser array has a beam divergence in the plane of the junction of about 9°.
文摘A fiber-coupled laser-diode (LD) end-pumped Nd:GdVO4 slab continuous-wave (CW) 912-nm laser and an LD bar end-pumped Nd:GdVO4 slab CW 912-nm laser are both demonstrated in this paper. Using the fiber-coupled LD of end-pumped type, a highest CW 912-nm laser output power of 10.17 W is obtained with a high optical to-optical conversion efficiency of 24.6% and a slope efficiency of 34.5%. The measured M2 factors of beam quality in x and y directions are 5.3 and 5.1, respectively. Besides, an LD bar of end-pumped type is used to realize CW 912-nm laser output, which has the advantages of compactness and low cost. When the pump power is 38.8 W, the output power is 8.87 W and the measured M^2 factors of beam quality in x and y directions are 16 and 1.31, respectively. In order to improve the beam quality of the 912-nm laser at x direction, a new quasi-concentric laser resonator will be designed, and an LD bar end-pumped Nd:GdVO4 slab high-power CW 912-nm TEM00 laser will be realized in the future.
文摘An overview of the applications of semiconductor lasers is presented. Diode lasers are widely used today, and the most prevalent use of the laser is probably in CD and DVD drives for computers and audio/video media sys- tems. Semiconductor lasers are also used in many other fields ranging from optical fiber communications to display, medicine and pumping sources.
文摘为了使半导体激光器的激光波长和输出功率稳定,必须对其温度进行控制。介绍了LD泵浦固体激光器恒温控制系统的软、硬件方面设计。温度采集电路采用具有高输入阻抗和高共模抑制比的测量放大电路,利用半导体制冷器(thermo electric cooler,TEC)作为控温系统的控温执行器件。由改变驱动TEC电流的方向来实现制冷或者加热,软件采用增量型防积分饱和的数字PID算法,根据实验结果温控控制精度在±0.5℃,可以满足对半导体激光器温度控制精度和稳定性的要求。