Monolithic Semiconductor Laser Beam Control

Because of the rapid development of the optoelectronic devices, especially the semiconductor lasers, LDs (Laser Diodes) have been used in more and more areas, including optical communication, solid-state laser pumping, laser processing, laser printing and medical applications. But the poor output beam quality of the edge-emitting semiconductor laser limits its further applications. How to improve the quality of the edge-emitting semiconductor laser beam becomes a widely concerned problem.There are two kinds of techniques to improve the beam quality of the LD. The first one is to alter the beam quality internally, such as adding external cavity to the LD or optimizing the structure of the LD cavity. The second one is to improve the beam quality exteriorly; the common method is to add optical elements in front of the laser beam.This thesis focuses on the exterior techniques to improve the beam quality of the edge-emitting LD. This kind of techniques is cheaper and can be realized more easily. Before the great breakthrough of the LD, the kind of techniques is the first choice.There are two main topics in the thesis: diode laser beam shaping and diode laser beam coupling. In the beam shaping part, a novel diode laser beam line generator and homogenizer, which has multiple applications in laser processing and laser printing, has been discussed detailedly. In the part of the beam coupling, the coupling between the high power single emitter broad area diode laser and cylindrical lensed multimode fiber has been analyzed amply. The use of the lensed fiber can improve the fiber output beam brightness greatly.The thesis includes four parts. The first chapter introduces the development and the characteristics of the semiconductor lasers. The former diode laser beam control techniques are discussed in the second chapter. The third part of the thesis discusses the novel laser beam line generator and homogenizer; and the results of the computer aided simulation of the beam line generator have been described too; the results verified the quality of the line generator.The coupling between the high power single emitter broad area diode laser and the cylindrical lensed multimode fiber has been discussed in the last chapter; in addition, the simulation and the experiment have been done to support the theoretical results. In the experiments, the maximum practical coupling efficiency is 87.06%, which is as two times as the maximum practical coupling efficiency between the same LD and the same multimode fiber without fiber micro-lens (39.41%).