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
This paper discussed the main parameters contributing to the measurement uncertainty of interferometric distance meter （IDM）. A simple and robust set-up is used to measure distance of about 12 cm with an expanded un...This paper discussed the main parameters contributing to the measurement uncertainty of interferometric distance meter （IDM）. A simple and robust set-up is used to measure distance of about 12 cm with an expanded uncertainty （ k = 2） of ±16.4 μm. The measurement uncertainty is found to be limited by the wavelength measurement accuracy. This set-up can be used to measure distances up to 56 m. It also enables easy determination of the point of equal path difference between the measuring and the reference arms. LabVIEW program is used for counting of the fringes and applying fast Fourier transfor- mation （FFT） to perform frequency selective filtration to the noise. Although the reported uncertainty does not represent the state-of-art uncertainty reached for similar distance, the measurement provides traceable measurement to the unit of length, the meter.展开更多
Two types of the dual mode-locked fiber lasers for asynchronous absolute distance measurement are investigated, The lasers are linear and ring cavity with repetition rate of 70 MHz and 100 MHz, respectively. The group...Two types of the dual mode-locked fiber lasers for asynchronous absolute distance measurement are investigated, The lasers are linear and ring cavity with repetition rate of 70 MHz and 100 MHz, respectively. The group velocity dispersion is not compensated in the first type of the lasers, while the others are fully done. The timing jitter with the Allan deviation below averaging time of 0.2 s during the distance measurement for around 1 m of both types of lasers were 2.5 ps with 600 nm and 1.6 ps with 200 nm. We concluded that the phase noise resulted from the intra-cavity dispersion is the main contribution for the uncertainty of the ranging in these two types of the lasers.展开更多
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.
文摘This paper discussed the main parameters contributing to the measurement uncertainty of interferometric distance meter （IDM）. A simple and robust set-up is used to measure distance of about 12 cm with an expanded uncertainty （ k = 2） of ±16.4 μm. The measurement uncertainty is found to be limited by the wavelength measurement accuracy. This set-up can be used to measure distances up to 56 m. It also enables easy determination of the point of equal path difference between the measuring and the reference arms. LabVIEW program is used for counting of the fringes and applying fast Fourier transfor- mation （FFT） to perform frequency selective filtration to the noise. Although the reported uncertainty does not represent the state-of-art uncertainty reached for similar distance, the measurement provides traceable measurement to the unit of length, the meter.
文摘Two types of the dual mode-locked fiber lasers for asynchronous absolute distance measurement are investigated, The lasers are linear and ring cavity with repetition rate of 70 MHz and 100 MHz, respectively. The group velocity dispersion is not compensated in the first type of the lasers, while the others are fully done. The timing jitter with the Allan deviation below averaging time of 0.2 s during the distance measurement for around 1 m of both types of lasers were 2.5 ps with 600 nm and 1.6 ps with 200 nm. We concluded that the phase noise resulted from the intra-cavity dispersion is the main contribution for the uncertainty of the ranging in these two types of the lasers.
