Experimental observation of bright-dark pulse emitting in an all-fiber ring cavity laser

We demonstrate the emission of bright pulse and dark pulse in a simple all-fiber ring cavity laser by using self-pulsing technique. The switching between bright pulse and dark pulse can be realized by properly rotating the polarization controller ( PC ). Meanwhile, the bright-dark pulse can also be generated in the fiber laser and is experimentally verified to be on two different orthogonal polarization axis of the cavity fiber. Our experimental results show that the bright pulse, the dark pulse or the bright-dark pulse can be obtained in an all-fiber laser by using self-pulsing technique.