红外激光照明实用化技术研究

发布时间：2018-02-12 02:33

本文关键词： 半导体激光器光纤耦合光束整形主动红外　出处：《西安电子科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着安防领域的发展,智能视频技术的不断出现,对夜间动态监控的要求越来越高,在油田、矿山、景区、森林防火、交通工程、城市反恐等方面需要进行夜间中远距离的跟踪监视。主动红外夜视技术是通过光源主动照射目标,利用目标反射光源的红外线来实施目标监控的一种夜视技术,产生这种不可见光的红外光源,最常见的是阵列式LED灯,这种光源电光转换率只有25%左右,多余的能量转换成热量,功耗很大,照射距离只有几十米,无法满足中远距离的监控要求。而半导体激光器作为新一代的红外光源,电光转换率达到50%以上,而且发射的激光在方向性、单色性方面也是LED灯无法比拟的,这使得半导体激光器成为不同于LED灯技术的新一代红外光源产品。本论文的研究目的是得到低成本、实用化的红外半导体激光光源,采用不同的工艺,开发出不同功率的半导体激光光源,满足现有的市场需求。优化激光器封装工艺,减少激光器芯片的热阻,提高激光器芯片的寿命和性能。开发光纤、合束光纤的组装、研磨和抛光工艺,使光纤端面满足红外半导体激光器耦合的要求。有了高可靠性的激光器芯片和高透过率的光纤、光纤束,就可以进行光纤耦合和光斑匀化的工作。激光器光束是椭圆的高斯光束,光束的垂直发散角较大,其光斑由于有高阶模式的存在而呈若干长条状,光斑不均匀。激光器光束若直接用于照明,照明效果很差,必需对其进行整圆和光斑均匀化处理。单个大功率激光器,目前常用方案是用两个激光器经过光学透镜压缩,重叠光斑,两个激光器的光斑互补后,可将一些暗条纹变亮,以此来提高均匀性。本论文将提供另一种低成本实用化方案,使用光纤和光学匀化片,来解决光斑均匀性问题。同时,为了满足几公里这种远距离的监控,激光光源采用列阵封装,光斑经过压缩和光纤耦合后,使用多纤芯捆绑的方式输出激光,其激光器输出功率高,性能可靠,使用灵活,光斑均匀的效果更好；通过微光学元件对激光器的光束进行整形、变换,再通过非球面透镜聚焦耦合到单根光纤中,这种多单管空间耦合激光器的体积小,功率密度高,亮度高,光束质量好。可以满足特殊要求的红外照明系统。最后,改进光纤的对接方式,提高对接效率,使红外激光器的输出功率更高,在满足光斑均匀性的同时,提高红外激光器的照射亮度和照射距离。
[Abstract]:With the development of security field and the continuous emergence of intelligent video technology, the requirement of dynamic monitoring at night is higher and higher. In oil fields, mines, scenic areas, forest fire prevention, traffic engineering, Active infrared night vision technology is a kind of night vision technology that actively illuminates the target through the light source and uses the infrared ray of the target reflected light source to carry out the target monitoring. The most common source of infrared light that produces this invisible light is an array of LED lamps. The electro-optic conversion rate of this light source is only about 25%, the excess energy is converted into heat, the power consumption is very large, and the radiation distance is only several tens of meters. Semiconductor laser, as a new generation of infrared light source, has an electro-optic conversion rate of more than 50%. Moreover, the directionality and monochromaticity of the emitted laser is unparalleled by LED lamp. This makes semiconductor laser a new generation of infrared light source products different from LED lamp technology. The purpose of this paper is to obtain low cost, practical infrared semiconductor laser light source and adopt different technology. The semiconductor laser light source with different power is developed to meet the existing market demand. The laser packaging technology is optimized, the thermal resistance of the laser chip is reduced, the lifetime and performance of the laser chip is improved, and the assembly of optical fiber and bundled fiber is developed. Grinding and polishing process to make the optical fiber end surface meet the requirements of infrared semiconductor laser coupling. With high reliability of the laser chip and high transmittance fiber, fiber bundle, The laser beam is an elliptical Gao Si beam, the vertical divergence angle of the beam is large, and the spot of the laser beam has several long strips due to the existence of higher-order modes. If the laser beam is used directly for illumination, the illumination effect is very poor, so it is necessary to deal with the whole circle and the light spot homogenization. At present, the common scheme for a single high-power laser is to compress two lasers through optical lens. Overlap spot, two laser spot complementary, can brighten some dark fringes to improve uniformity. This paper will provide another low-cost practical solution, using optical fiber and optical homogenization, To solve the problem of spot uniformity. At the same time, in order to meet the remote monitoring of several kilometers, the laser light source is packaged in array. After compression and optical fiber coupling, the laser is output by multi-core binding. The laser has the advantages of high output power, reliable performance, flexible use and uniform spot. The laser beam is shaped, transformed and coupled to a single optical fiber by focusing through an aspheric lens. The multi-tube space coupled laser has the advantages of small volume, high power density, high brightness and good beam quality. It can meet the special requirements of the infrared illumination system. Finally, the docking mode of the optical fiber is improved and the docking efficiency is increased. The output power of the infrared laser is higher, and the illumination brightness and the irradiation distance of the infrared laser can be improved at the same time as the uniformity of the spot.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN248

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