Polarization And Spectrum Properties Of Vertical-Cavity Surface-Emitting Lasers

Vertical-cavity surface-emitting lasers (VCSEL) have distinct advantage over conventional edge emitting lasers. In VCSEL, the material gain and wave-guide anisotropy are considerably reduced because of their cylindrical symmetry and their surface emitting. So lead to their polarization behavior not as well as edge lasers. And because VCSEL's cavity is very short, it's easily worked in one mode. The main work is as follows:Part Ⅰ .Without consideration the applied strain and temperature, we resolved numerically the Maxwell-Bloch equation through four-energy level polarized dynamic model. And we studied the intensity of emergent polarized light, frequency, phase variation about VCSEL caused by the injection current and anisotropic change. The paper demonstrates that the output light occurs polarization switching as the increasing of the injection current theoretically and experimentally. We measured experimentally the change of emergent polarized light.Part Ⅱ. We are researched the factor of affected the VCSEL spectrum characteristic, and come to conclusion some characteristics of the VCSEL spectrum, get some factors of the influence VCSEL spectrum characteristics. Pass to the experiment, we are measured three VCSEL's spectrum characteristics and explained it in theory. We make some ideas to improve it.Part Ⅲ. We studied the relations between the VCSEL's polarization properties and spectrum properties, when the output light occurs polarization switching as the increasing of the injection current we may observe two modules closed, but when one polarization output light is strong and the other is weak, the VCSEL may worked in one module.The results showed that the unstable factors of VCSEL's emergent polarized light are aniso- tropic effect. We deduced theoretically that the polarized light change with the increase of injection current and measured experimentally the process of polarized light's direction change with the injection current. For the VCSEL's spectrum, in theory it can work in one mode, but actually the condition is very complexity.