A superluminescent diode (SLD) as an alteative of laser is used to detect optical rotation for atomic spin precession.A more uniform Gauss configuration without additional beam shaping and a relatively high power of the SLD have a potential for atomic magnetometers,which is demonstrated in theory and experiments.In addition,the robustness and compactness enable a more practical way for optical rotation detections,especially for applications in magnetoencephalography systems.