Capacity to generate random signals by semi-nonlinear coupler

Abstract

The semi-nonlinear coupler (SNC) is used to split an optical signal into two different amplitude signals, and to reshape a series of signals. The mentioned applications are based on the monotonical dependence of the transmission coefficients on the input intensity, which changes in an interval. In this paper, we show that there is a certain interval of input intensity, in which the transmission coefficients overlap one to other. This behaviors of SNC can be used to generate random signals. Using the expression described the output-input power relation, the expression of the optical merge signal, carrier signal and coded-carrier signal, the overlapping region of the input intensity is numerically observed. Consequence, the random signals are simulated. The obtained signals are discussed to show the opportunity to use them for the information security of the wireless or free-space optical communication in the future.