Characteristics Of Slow Light According To Four-wave Mixing Effect Based On Soa

All-optical storage and cache are the key technologies for resolving the competition of the output data and achieving all-optical routing in optical packet switching network. How to make optical storage and optical information processing successful by slowing down the group velocity of light wave has become one of the hot topics both at home and abroad in recent years. Semiconductor optical amplifier (SOA) is small in cubage, easily integrated and compatible with optical fiber communication system. Thus at room temperature, both of fast and slow light can be obtained via the four-wave mixing (FWM) effect in SOA. The thesis selects travelling wave SOA as the research material and conducts a theoretical analysis and numerical calculation of the time delay characteristics of slow light based on nearly degenerate four-wave mixing (FWM) in SOA. The main contents are as follows.(1) The research analyzes the gain saturation effect of traveling wave SOA by applying segment numerical model of SOA. The simulation results indicate that excessive input optical power leads to gain saturation phenomenon in SOA. Increasing the bias current, to some extent, relieves the saturation effect, but at the same time it will reduce the input saturation power of SOA.(2) The thesis explores the characteristics of the optical gain based on nearly degenerate FWM effect in SOA, and it analyzes the variation of conversion efficiency of the conjugate light, transmittance of signal light with respect to linewidth enhancement factor, input pump power as well as bias current. The conversion efficiency of the conjugate light can be improved by increasing the bias current and linewidth enhancement factor and by adding input pump power reasonably. The variation range of transmittance of signal light with respect to frequency detuning can also be enlarged by these two methods. Excessive input pump power leads to the decline of conversion efficiency of the conjugate light and transmittance of signal light.(3) The research discusses the time delay characteristics of slow light under steady state conditions according to nearly degenerate four-wave mixing effect of SOA. Firstly, the thesis quantitatively simulates the numerical relations between the delay of slow light and bias current, frequency detuning, as well as pump power. Secondly, the thesis analyzes the influence of the transformation of input pump power and carrier spontaneous radioactive lifetime on the operating bandwidth of slow light. Finally, by the finite difference method, the author conducts a numerical calculation of coupled wave equations in the case of transient FWM, analyzing the variation of such parameter as the signal light pulse delay volume and peak power with the frequency detuning, bias current.In the process of obtaining slow and fast light with nearly degenerate four-wave mixing effect of SOA, the amount of signal light delay can be controlled by adjusting such parameters as frequency detuning, bias current and pump power. Before the SOA works in saturation regime, delay of signal light increases with the increase of bias current and input pump power. Excessive input optical power leads to the decline of the amount of signal light delay. The greater the bias current, the smaller the pump power resulting in the decline of the amount of signal light delay is. A higher operating bandwidth of slow light can be achieved by increasing the input pump power. Relatively large carrier lifetime enhances the maximum amount of time delay, but meanwhile it to some extent compresses the operating bandwidth.