Abstract: We proposed a scheme of injecting chaotic laser into semiconductor ring lasers (SRL) to otain the time delay signature (TDS) of chaotic laser and increase its bandwidth. In this scheme, the master lasers was a distributed feedback semiconductor lasers with double phase modulation optical feedback in the outer cavity, and chaotic laser output was simultaneously injected into both clockwise and counterclockwise modes of the SRL, thus forming a SRL system with dual modes optical injection from external chaos light （SRL-DMOIECL）. We numerically studied the influence of parameters such as external light injection coefficient and feedback coefficient on the TDS of the output chaotic laser of the system. The maximum value of the time delay signature peak in the autocorrelation function curve was used to represent the time delay signature value. The suppression effect of this system on TDS was compared with that of the SRL system with single mode optical injection from external chaos light (SRL-SMOIECL), and the bandwidth of chaotic laser from the system was studied. The results show that the scheme has a better suppression effect on TDS, which  can effectively suppress the TDS of the output chaotic laser and increase its bandwidth, the maximum 3 dB bandwidth can reach 19 GHz.

Key words: semiconductor ring laser, chaotic laser, phase modulation, time delay signature, bandwidth