We proposed a simple model for generation of controllable ultraslow optical solitons of a weak probe laser light in a degenerated two-level atomic medium under electromagnetically induced transparency assisted by a magnetic field. It is shown that bright and dark optical solitons can be formed from a probe light with controllable ultraslow group velocities at a few m/s by tuning the strength of a coupling light and/or the magnetic field. In addition to the ultraslow velocity, the advantage of this model is to use a sole laser for delivering both pump and probe lights. Furthermore, one can switch between bright and dark solitons by reversing the direction of the magnetic field. Such controllable ultraslow solitons are interested in finding applications in optical communications and optical data processing.

我们提出了一个简单的模型，用于在磁场辅助的电磁感应透明下在退化的两能级原子介质中生成弱探测激光的可控超慢光孤子。结果表明，通过调节耦合光和/或磁场的强度，可以从具有可控超慢群速度的探测光形成明暗光孤子，速度可达几米/秒。除了超低速度外，该模型的优点是使用唯一的激光器来提供泵浦光和探测光。此外，人们可以通过反转磁场方向在明暗孤子之间切换。这种可控的超慢孤子有兴趣在光通信和光数据处理中找到应用。