Study Of Gain And Temporal Character Of Fiber-optic Parametric Amplifier

Fiber-optic parametric amplifier (FOPA) is a new kind of nonlinear all-optical amplifier based on four-wave mixing. It has many excellent characters such as high gain, large bandwidth, and low noise figure, which makes it have the potential applications in the all-optical amplifier and in all optical signal processing. Because of some intrinsic limitations, however, there are some pressing issues in the application of FOPA. These issues include the impacts of polarization dependence, temperature, other nonlinear effect under high power conditions, and crosstalk of different channels and the saturated effect of signal when FOPA is employed in the DWDM system, and so on. After systematic review of these problems, we investigate the properties of gain and bandwidth of FOPA in the saturation amplification regime and signal pulse evolution in the FOPA by using the analytical simulation. The main results are as follow:Firstly, FOPA has different models when different assumptions are used. In order to show the main physical process and simplify the analysis, we have independently developed the computer codes which can simulate both the gain spectrum of FOPA and the signal pulse evolution in the FOPA based on the model of single pump FOPA and the model including the dispersion in the pulse.Secondly, the properties of gain and bandwidth of FOPA in the saturation amplification regime are analyzed. We have described the relation between gain spectrum and fiber length, the power of the input signal, the wavelength separation between zero dispersion wavelength and pump wavelength. It is found that the gain in the saturation amplification regime drops and the gain bandwidth is smaller than that in small signal amplification regime. In addition, there are side lobes in the gain bandwidth. These results are helpful to the design of one-pump fiber optical parametric amplifier in the saturation amplification regime.Thirdly, we investigate the temporal character of FOPA. The evolution of profile of the signal along FOPA is analyzed. In order to show the general result, the normalized model including the dispersion in the pulse is employed. The change of the profile of continuous optical wave in FOPA is obtained by numerical analysis. The impact of phase mismatch on the temporal character of FOPA is demonstrated. Particularly, we have investigated the evolution of the profile of the signal along the...