Time filter

Source Type

Xue Y.,CAS Shanghai Institute of Optics and fine Mechanics | Xue Y.,Shanghai Key Laboratory of All Solid State Laser and Applied Techniques | Xue Y.,University of Chinese Academy of Sciences | He B.,CAS Shanghai Institute of Optics and fine Mechanics | And 12 more authors.
Chinese Optics Letters | Year: 2012

Array size scaling of passive coherent beam combination is explored theoretically. The Strehl ratio variation with wavelength is simulated in 4-, 9-, 16-, and 25-channel fiber arrays. The average Strehl ratio and phase error are calculated. The Strehl ratio is found to be near 100% for arrays with less than 5 fibers, but decreases significantly for larger arrays. These results are in good agreement with the recent experimental results. © 2012 Chinese Optics Letters.


Wang J.-W.,Jiangnan University | Su Z.-P.,Jiangnan University | Su Z.-P.,Wuxi Led Electronics Company | Yuan Z.-J.,Shanghai Key Laboratory of All Solid state Laser and Applied Techniques | Zhu Y.-Q.,Jiangnan University
Guangzi Xuebao/Acta Photonica Sinica | Year: 2014

Global optimization algorithm was proposed to optimize and design LED array for generating uniform illumination distribution on target plane. An evaluation function reflecting illumination uniformity was constructed, which can reach the minimum by optimizing the LEDs positions. While the evaluation function takes the minimum value, the optimal LED array can produce highly uniform illumination distribution on target plane. The minimum value of evaluation function was found by simulated annealing algorithm, so that the circular array consisting of 12 LEDs, 4×4 and 4×5 rectangular LED array were optimized. After optimization, the three arrays produce highly uniform illumination distribution with the calculated uniformity 97%, 96% and 95%, respectively. The results show that the optimal radius of circular array does not depend on the number of LEDs. The optimal radius depends linearly on the distance between LED array plane and the target plane. For the rectangular array, the optimal separation between adjacent LEDs depends linearly on the distance between LED array plane and the target plane. The results of the proposed method were consistent with existing method, and the algorithm is simple and convenient.


Wu W.,Qufu Normal University | Wu W.,CAS Shanghai Institute of Optics and fine Mechanics | Wu W.,Shanghai Key Laboratory of All Solid State Laser and Applied Techniques | Wang H.,Qufu Normal University | And 5 more authors.
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2014

In order to make quantitative analysis to the accuracy crystal thickness in the birefringent filters, based on the fundamental filter theory, by introducing the birefringent dispersion of crystal, the exact relationship of crystal thickness accuracy, phase retarder deviation and spectrum shift is built up. Theoretical analysis and simulation are put forward strictly. The results show that the birefringent dispersion cannot be neglected when using LiNbO3 as the materials of plates and that the crystal thickness accuracy can ensure a good transmission spectrum, which may be useful for constructing high-performance birefringent filer. ©, 2014, Science Press. All right reserved.


He J.,CAS Shanghai Institute of Optics and fine Mechanics | He J.,University of Chinese Academy of Sciences | He J.,Shanghai Key Laboratory of All Solid state Laser and Applied Techniques | Du S.,CAS Shanghai Institute of Optics and fine Mechanics | And 8 more authors.
Optics Express | Year: 2013

A linearly-polarized, high peak power, short-pulse, Q-switching Yb-doped large-mode-area photonic crystal fiber (PCF) oscillator with three-level system operation is demonstrated. By optimizing cavity parameters and adopting linear polarization component, the laser can easily obtain linearlypolarized output over 2 W at 978 nm with polarization extinction ratio (PER) up to 43 dB without any additional wavelength filter. Less than 50 ns stable output pulses are achieved within repetition range of 10 kHz-200 kHz and short pulse of 9 ns pulse duration, 130 kW peak power at 10 kHz can be reached. The characteristics and the key issues of the laser, such as interpulse ASE, spectrum ASE around 1030 nm, are with detailed discussion in the paper. © 2013 Optical Society of America.


Yang J.,CAS Shanghai Institute of Optics and fine Mechanics | Yang J.,Shanghai Key Laboratory of All Solid State Laser and Applied Techniques | Yang J.,University of Chinese Academy of Sciences | Hou X.,CAS Shanghai Institute of Optics and fine Mechanics | Hou X.,Shanghai Key Laboratory of All Solid State Laser and Applied Techniques
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2010

Splitting performance of two parallel plates is analyzed and a design method is presented to optimize their splitting performance. Two parallel plates parallel to each other split one incident laser beam into multiple beams which are detected by a CCD camera. Because of the use of CCD camera, difference of maximum power density between received laser faculae(DMPF) should be made as little as possible. Effect of distance between plates and incident angle on difference of laser faculae is analyzed. And the calculation results show that reasonable selection of distance between plates and incident angle can minimize DMPF. The optimum distance between plates increases as Rayleigh length of laser beam increases while the optimum incident angle keeps stable under the condition of fixed coated film and fixed central wavelength of laser beam. And DMPF under corresponding optimum conditions fluctuates as Rayleigh length increases.


Tang H.,CAS Shanghai Institute of Optics and fine Mechanics | Tang H.,Shanghai Key Laboratory of All Solid State Laser and Applied Techniques | Zhu X.,CAS Shanghai Institute of Optics and fine Mechanics | Zhu X.,Shanghai Key Laboratory of All Solid State Laser and Applied Techniques | And 4 more authors.
Guangxue Xuebao/Acta Optica Sinica | Year: 2010

An electro-optic (EO) Q-switched Nd:YVO4 laser with high repetition rate of 30 kHz, end-pumped by a continuous-wave (CW) laser diode (LD) is reported. Using La3Ga5SiO14 (LGS) single crystal as an EO Q-switch and designing an efficient and stable resonator, the repetition rate of EO Q-switched operation can be changed from 1 Hz to 30 kHz. Using an output coupler with transmittance of 50%, an output pulse train with pulse energy of 0.4 mJ and pulse width of 6.3 ns is obtained at the repetition rate of 5 kHz. An average output power of 6.2 W with the pulse width of 9.1 ns is obtained when the repetition rate reaches 30 kHz, the slope efficiency and dynamic to static ratio are 32.7% and 83%, respectively. The beam transfer factor M2 is measured to be less than 2. Experimental results show that the output level has great potential for further development.


Fan Y.,CAS Shanghai Institute of Optics and fine Mechanics | Fan Y.,Shanghai Key Laboratory of All Solid State Laser and Applied Techniques | Fan Y.,University of Chinese Academy of Sciences | He B.,CAS Shanghai Institute of Optics and fine Mechanics | And 15 more authors.
Optics Express | Year: 2011

Thermal effects and output power characteristics of kilowatt allfiber master-oscillator power amplifier (MOPA) are investigated. Proper designs for cooling apparatus are proposed and demonstrated experimentally, for the purpose of minimizing splice heating which is critical for the reliability of high power operation. By using these optimized methods, a thermal damage-free, highly efficient ytterbium-doped doubleclad fiber MOPA operating at 1080 nm with 1.17 kW output was obtained. The maximum surface temperature at the pump light launching end splice of the booster amplifier was 345 K, and the temperature rise for this key splice was 0.052 K/W. © 2011 Optical Society of America.


Wang W.,CAS Shanghai Institute of Optics and fine Mechanics | Wang W.,Shanghai Key Laboratory of All Solid State Laser and Applied Techniques | Wang W.,University of Chinese Academy of Sciences | Lou Q.,CAS Shanghai Institute of Optics and fine Mechanics | And 14 more authors.
Chinese Optics Letters | Year: 2010

The characteristics of fiber laser coherent beam combination are investigated by using a 2×2 fiber laser array with a self-Fourier cavity. The experimental results show that with a certain output width the power ratio of the center spot is increased with the increase of space duty cycle, meanwhile the number of secondary spots is decreased correspondingly. The results are in agreement with theoretic analysis. © 2010 Chinese Optics Letters.


Yang Y.,CAS Shanghai Institute of Optics and fine Mechanics | Yang Y.,Shanghai Key Laboratory of All Solid State Laser and Applied Techniques | Yu D.,CAS Shanghai Institute of Optics and fine Mechanics | Yu D.,Shanghai Key Laboratory of All Solid State Laser and Applied Techniques | And 4 more authors.
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2011

A novel drive power for narrow pulse laser diode, which is composed of driving circuit and temperature controlling circuit, has been designed. High speed metal-oxide-semiconductor field effect transistor (MOSFET) is applied in the driving circuit as the switch to provide the laser diode with smooth pulse of high repetition rate (0-50 kHz), fast rise time (2.2-4.9 ns), narrow pulse width (4.6-12.1 ns) and high peak pulse current (0-72.2 A). According to the requirements of variety of laser diodes, different repetition rates, rise time, pulse widths and peak pulse currents can be achieved by varying the voltage, resistor, capacitor in the circuit. A precise proportional-integral differential (PID) temperature controlling module is adopted in the circuit to ensure the stability of the output power and the central wavelength of the laser diode. The drive power can be not only used as the power supply for the traditional high speed, narrow pulse width laser diode, but also an ideal drive power for the high energy, narrow width pulse laser diode.


Zhou T.,CAS Institute of Mechanics | Chen W.,CAS Institute of Mechanics | Chen W.,Shanghai Key Laboratory of All Solid State Laser and Applied Techniques | He Y.,CAS Institute of Mechanics | And 3 more authors.
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2010

Lidar has been used for ocean remote sensing widely. The upward laser beam is distorted due sea surface. It Iimits dramatically laser transmission through sea surface and the application of Lidar under water. The beam distribution of upward laser beam through sea surface is studied based on the geometrie optical theory, three dimension wave simulation and Monte Carlo simulation respectively. Results show similar beam distribution by the three methods. The beam profile is limited in ±10° for collimated vertical upward beam. Demonstrati distribution through man-made rough water surface is conducted in a water tank. Results show that the exit angle is actually limited within ±10°. The study will be useful to the design of Lidar application under sea water.

Loading Shanghai Key Laboratory of All Solid state Laser and Applied Techniques collaborators
Loading Shanghai Key Laboratory of All Solid state Laser and Applied Techniques collaborators