Influences Of The Strong Light Injection On The Chaotic Carrier Fundamental Frequency Of VCSELs With Optical Feedback

As a new kind of semiconductor laser, vertical-cavity surface-emitting lasers(VCSEL) have such merits as low threshold, single longitudinal mode operation, small angle of divergence, high dynamic modulating frequency, easily implemented two-dimension integration which makes VCSEL have significant implication prospects in optical communication, optical interconnection, image signal processing, etc. As a result, the researches on VCSEL have been paid special attentionRecently, Chaos private communication has get an extensive application, optical chaos become a hot topic of private communication for a fundamental phenomenon of nonlinear dynamics and highly sensitivity to the parameters, the rate of transmission is one of the most important Index sign in chaotic communication which is determined by the chaotic carrier fundamental frequency. Carrier frequency is closely related to the relaxation oscillation frequency, and the relaxation oscillation frequency is considered to be the characteristic frequency that defines the maximum modulation frequency of a semiconductor. At present, the experiments focused on the VCSELs, where a relaxation oscillation frequency 50GHZ was achieved, therefore we can anticipate, the chaotic carrier fundamental frequency of VCSEL's output with optical feedback can be enhanced by using the external optical injection technique.In this paper, the influences of the external light injection on the chaotic carrier fundamental frequency of VCSEL with optical feedback have been investigated. The results show that in the injection locking area, for the fixed frequency offset between the master laser diode and the slave VCSEL, the chaotic carrier fundamental frequency will be increased generally with the increase of injected strength, accompany with motion in the process of increase; Simultaneously, the frequency offset have the important influence to the chaotic carrier fundamental frequency, when the frequency offset is positive, the chaotic carrier fundamental frequency also increased generally with the increase of the frequency offset, chaotic carrier fundamental frequency can be improved significantly by adjusting frequency offset and injected strength. For the normalized injected strength K is 330 and frequency offset is 42GHz, chaotic output with 47.3GHz fundamental frequency can be obtained. Therefore, the investigation in this paper has the high research value for improving the transmission rates.