1550nm-VCSELs在偏振保持光反馈和正交光注入下的偏振转换特性

Polarization switching characteristics of polarization maintaining optical feedback and orthogonal optical injection of 1550 nm-VCSEL

基于自旋反转模型,研究了1550 nm垂直腔面发射激光器(1550 nm-VCSELs)在偏振保持光反馈和正交光注入下的偏振转换特性.结果表明:正交光注入下的从激光器会随着注入强度的增加产生偏振转换.在归一化注入电流较小时,改变反馈强度,会使从激光器发生偏振转换的注入强度出现规律不同的变化;改变频率失谐,会使从激光器发生偏振转换的注入强度出现规律相同的变化.

Based on the spin flip model, four schemes for the polarization switching of the 1550 nm vertical cavity surface emitting laser are studied by using numerical simulation, which are free running laser orthogonal injection free running laser, free running laser orthogonal injection polarization maintaining optical feedback laser, polarization maintaining optical feedback laser orthogonal injection free running laser, and polarization maintaining optical feedback laser orthogonal injection polarization maintaining optical laser. We can draw three conclusions from the numerical results. Firstly,changing the feedback strength can make the polarization switching point of the injection intensity in the different regular movements when the normalized injection current is small. The injection intensity of the polarization switching point increases with the increase of the feedback strength for the free running laser orthogonal injection polarization maintaining optical feedback laser; the injection intensity of the polarization switching point decreases with the increase of the feedback strength for the polarization maintaining optical feedback laser orthogonal injection free running laser;the injection intensity of the polarization switching point is nonlinear and fluctuates with the increase of the feedback strength for the polarization maintaining optical feedback laser orthogonal injection polarization maintaining optical laser. The reason is that the non dominant X polarization component cannot go up when the normalized injection current is small, then, as the feedback intensity increases, the difference between the two polarization components will be increased. Secondly, when the normalized injection current is large, changing the feedback intensity can make the polarization switching point of the injection intensity in the irregular movement. The reason is that the non dominant X polarization component can go up when the normalized injection current increases up to a certain value, which can form the significant nonlinear wave together with the dominant Y polarization component. Thirdly, changing the frequency detuning can make the polarization switching point of the injection intensity in the same regular movement. The injection strength required for the occurrence of polarization switching point first decreases and then increases for the four schemes, when the frequency detuning is from approximately-60 GHz to the minimum, presenting the symmetrical distribution of ＂V＂ type with-60 GHz as the axis. The same regular movement of the polarization switching point of the injection intensity is not changed with the change of the normalized injection current.