Research On Chaotic Bandwidth And Polarization Switching Of Semiconductor Laser System

Semiconductor lasers as one of the mainstream light sources,additional freedom(optical feedback,optical injection and photoelectric feedback)enable it achieving chaotic light output.Chaotic laser plays an important role in confidential communication.Because of this,it's very important to research the widening of the bandwidth of chaotic lasers,the hiding of time delay characteristics and the polarization switching of VCSELs.In this paper,the following two aspects have been researched for the influence of the parameters of semiconductor lasers on the output chaotic signal.(1)For edge emitting semiconductor lasers,the relationship between the parameters of the four schemes(single optical feedback(SOF)scheme,double optical feedback(DOF)scheme,single photo injection(SPI)scheme and double photo injection(DPI)scheme)and time delay characteristics and bandwidth widening have been found based on the rate equations of chaotic systems.And then compare the merits of each schemes.It is found that the parameters such as feedback intensity,bias current,injection intensity and detuning have obvious influence on the delay characteristic and bandwidth of the output of chaotic signal.Selecting the appropriate parameter interval can suppress the time delay characteristics of the semiconductor laser from 0.4755 to 0.07485.At the same time,we can broad the bandwidth of the output chaotic signal from 17.9GHz to 28.47 GHz.(2)Based on the spin flip model,four schemes for the polarization switching of the 1550 nm vertical cavity surface emitting laser studied by using numerical simulation.The research shows that the increase in the injection intensity causes the polarization switching of slave laser with orthogonal optical injection.When the injection current is small,changing the intensity of the feedback causes a change in the intensity of the injection of the polarization switching of slave laser.Changing the detuning frequency causes the injection intensity of the polarization switching of slave laser to change in the same direction.