The research on beam shaping of stack pulse laser diodes (LDs), which have little emitter interval and bigger
discreteness, by means of the technology of photolithography, filming, precision position adjusting and fiber cylindrical
lens array, and on relative technologies are introduced in this paper. To obtain high peak power, which is in need of
application fields such as laser ranging, laser fuse, laser guidance, gate imaging and laser radar, direct stacking pulse LDs
are widely adopted, but the research on the relative beam shaping technology is done seldom. Owing to the micro-lens is
processed once only during the fabrication and the range interval of it is fixed, technologies now available is difficult to
take account of beam shaping and the interval discreteness of stack pulse LDs. The most advantageous of fiber
cylindrical lens array introduced in this paper is that it can adjust precisely every unit in the array respectively according
to the real emitting interval of stack pulse laser diodes, and carry out beam shaping effectively. After that the high
effectively coupling of multi-mode fiber can be realized. Thus the practical effect of stack pulse LDs is improved in a
Semiconductor laser has the characteristic of high efficiency and small volume,which make it be the best illuminator in the night vision system so that increase the range of observation and improve the image quality of night vision system. But in bad weather, image qualitly will decline because of atmosphere's backward scattering which serious influence the laser beam. To solve this problem, We have studied how to control the working condition of semiconductor laser and make it form a pulse laser which according with range gating technology in night vision system. The result of study indicates that semiconductor laser is feasible as illuminator for night vision system.
Proc. SPIE. 5628, Semiconductor Lasers and Applications II
KEYWORDS: Signal attenuation, High power lasers, Resistance, Semiconductor lasers, Heatsinks, Digital electronic circuits, Digital electronics, Failure analysis, Electrical breakdown, Temperature metrology
The attenuation of diode laser bar depends on the level of productive art and working condition, and the devices which attenuate quickly appear higher junction temperature and asymmetry of heat distributing. This paper introduces the research on the attenuation character of GaAs/AlGaAs diode laser bar, and obtains imitate curve of relation between PN junction voltage and junction temperature through plentiful experiments. At the same time, we draw the instantaneous thermal resistance through calculation. Based on the electrical method instantaneous thermal resistance and aging experiment, we have realized evaluating the attenuation character of diode laser bar without any damnify. Moreover, we have raised modification measure which based on analyzing the correlative art.
This paper introduces method of electrical noise evaluating of high-power fiber coupled diode laser. After photoelectricity conversion of output laser, We measure its electrical noise by analyse and test system. At the same time, we find out primary noise source through analysing 1/f noise, G-R noise and burst noise in the device systematically. Moreover we raise feasible advice on how to improve arts level and reliability of system after analysing relationship between noise and correlative arts. Experimental result shows that this method is effective and practicable .
With its study going deep into, the application field of semiconductor laser is increasingly broaden. But the asymmetry of far-field beam of semiconductor laser restricts its application. This article constructs a semiconductor laser current driving mode of high frequency and multi-wave. Through experiment, we present the best driving mode, which can uniform the far-field beam of semiconductor laser, and offer the result of the experiment at the same time.
With the development of science and technology, gunsight have made great progress. This paper introduces the working principle and structure of semiconductor laser gunsight that can be used day and night. The most excellence of which is that it can be used in the condition of zero illuminance. At the same time, we have developed an electrical cross line adjusting system which can lock goals easily. This kind of gunsight can be applied in the fields of the military, common security and civil affair.
It is a difficult problem to collect the information of accident in the detection system of traffic information. The paper states the principle of scanning the vehicles along the road with semiconductor laser .We can judge the moving state of the vehicles by distance image which is got by laser beam scan. The moving state will be abnormal in case the accident happens. This paper present the forming technology of scanning beam by semiconductor laser and the principle of software to dispose the distance image. This technology may also apply to other relative fields.
The paper introduces a research on fiber coupled CW diode laser module. It works in a series connection other than parallel connection, which is done by other devices. Through the study and optimization on technology of heatsink insulate, narrowband reflector, exact coupling compound and collimation, we have secured 10~20W output power from fiber which have 100µm core diameter when the working current is only several ampere. Because the total junction capacitance in series connection is small, it is easy to carry out narrower pulse direct modulation .All of these characters make it more suit the arm equipment which use batteries to power supply. Especially in these fields such as laser beam riding guidance, active image and night vision system, it may have good foreground.
The extreme divergence and the astigmatism of the high power laser diode array (LDA) require optics with complex lens structure and high performance. A monolithic micro- optic system is designed to shape the beam of LDA and couple the output of LDA with low NA fiber. The structure and principle of the micro-optic system is described in detail. The actual performance of the micro-optic system is studied by measuring P-I properties for both fiber coupled output and the LDA output, and their dependences on deviations in x, y, z directions. The light output of 980nm, 19-emitter LDA is shaped by this micro-optic system and coupled into a fiber with 400µm diameter, Numerical Aperture (NA) 0.22. The overall efficiency is more than 60%. The main factors effecting coupling efficiency are analyzed.