Analysis of frequency tuning process of dual coupled optical microcavities

Abstract

Different frequency detuning can excite different working mode in a dual coupled optical microcavities. Based on the nonlinear Schrödinger equations of dual coupled field, and by using the split-step Fourier method, the optical field evolution in the microcavities is analyzed under the condition of both positive and negative tuning, and various optical distributions are generated in the process of frequency tuning. Simulation results indicate that the field can develop into the bright soliton in the region of positive tuning. However, the region in which the bright soliton is maintained is small, and the field in the microcavities grows into direct current (DC) distribution because of the serious frequency detuning. In the region of negative tuning, the field of “turning pattern” with high power is generated. There is only chaos inside the microcavities without frequency detuning or the detuning parameters close to 0. In addition, under the condition of strong coupling, the bright soliton and the “turning pattern” cannot be excited. Even stronger coupling leads to optical field in the form of DC directly. After the bright soliton exciting in the microcavity, it can be preserved by selecting appropriate detuning parameters and pump power. Moreover, the bright soliton can be changed into “turning pattern” with low power by continuously changing the detuning parameter of the first microcavity. Theoretical analyses are significant for experimental research on the dual coupled microcavities.