BANDWIDTH ENHANCEMENT IN CHAOTIC SEMICONDUCTOR LASERS WITH STRONG CHAOTIC OPTICAL INJECTION

The bandwidth properties of chaotic signals generated by semiconductor lasers subject to strong chaotic optical injection (COI) are investigated numerically. The chaotic output of an injection master laser (ML) is injected into the slave laser (SL). The effects of feedback strength, injection strength and bias current on the bandwidth properties are discussed in detail. Some novel results are found, the bandwidth for SL increases with the injection strength firstly until reaches a maximum, and then decrease to approach the bandwidth of ML due to the injection-locking chaos synchronization. Large feedback strength and bias current contributes to higher maximum chaotic bandwidth in the range of injection strength. That is to say, for given parameters, optimal injection strength exists contributing to highest chaotic bandwidth, and moves to a large value for a large feedback strength and bias current, which is extremely useful for increasing the transmission rate of the optical chaotic communication system.