Two-Mode Coexistence in 1550-nm VCSELs With Optical Feedback

Two-mode coexistence in 1550-nm vertical-cavity surface-emitting lasers with optical feedback is experimentally investigated in detail. With the increase of the feedback strength, the two-mode coexistence region is enlarged for continually varied current. The feedback delay time has little influence on the two-mode coexistence region distribution under our experimental conditions. Moreover, a mapping of polarization-mode suppression ratio between two linear polarization (LP) modes is presented in the parameter space of the bias current and the feedback strength. In addition, the simultaneous chaos outputs of two LP modes are obtained for a certain two-mode coexistence region.