For many astronomical systems, Adaptive Optics (AO) plays an important role. Here, we report some preliminary studies
on MEMS (Micro-Electro-Mechanical-System) Project for micro actuators in AO applications at the Institute of Optics
and Electronics, Chinese Academy of Science. This paper presents a few MEMS actuators based on repulsive
electrostatic driven mechanism, which can achieve large out-of-plane strokes through eliminating the electrostatic pull-in
effect. Design principles, including the layout and the physical dimension of electrodes, and FEA models are illustrated;
it provides helpful guidance for designing electrostatic repulsive actuators for being implemented in Deformable Mirrors
(DMs). Some repulsive electrostatic driven micro actuators are given, the analysis focus on the displacement versus
applied voltage and resonant frequency. Repulsive electrostatic driven actuators can achieve large strokes and high
resonant frequencies, they meet the important requirements for DMs.
This paper focuses on the study of sensitivities of microcantilever chemical sensors based on SOI POLYMUMPS
process. Through changing the geometry of beams and analyzing resonance frequency shift in a dynamic mode by using
FEA (finite element analysis) method, the most sensitive structure, which is a triangle, is selected out from various kinds
of beam designs. The relation between the sensitivity and the parameters such as length L, width W and thickness t is
obtained by dynamic analyzing with the commercial software Intellisuite. This research provides the primary instruction
for developing high sensitive multi-array biochips aiming at analyzing multiple parameters in parallel.
Based on beam characteristic of semiconductor lasers, The paper details a pumping system, which couples single LD to multimode with hyperboloid micro-lens at first, and then combines sixteen LD fiber coupled modules which with 2W output power to parallel pump fiber lasers which with fiber Bragg grating on each end by using a multimode coupler at each end. The total conversion efficiency of optical to optical is 40% and output power from fiber is 13W. Because this pumping system has merit of small volume, compact structure, replaced easy, long lifetime and high pumping efficiency, it more fits to end and side pumping for fiber lasers.
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 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.
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.
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.
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.
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.