Research on pulse transmission characteristics based on combined dispersion- decreasing fiber loop mirror

The generation of effective ultra-short laser pulses in the picosecond pulse range is very important for modern communication. This paper firstly investigates a combined dispersion-decreasing fiber (DDF) loop mirror consisting of a fourth-order super-Gaussian DDF and a Gaussian DDF. First, the transmission principle of the designed fiber loop mirror is analyzed theoretically. Secondly, the influence of the total fiber length on pulse compression is studied to obtain an optimal total fiber length. Then the length ratio of the two optical fibers in the loop mirror is analyzed and optimized to achieve a high-quality ultra-short output pulse. The results show that the optimal output pulse with no pedestal and a high compression factor of F=49.6 can be obtained at the total fiber length L=4.3km and the combined fiber length ratio of the fourth-order super-Gaussian DDF and the Gaussian DDF is equal to 0.102. Compared with the traditional DDF loop mirror, the compression factor is increased by 18.5 times, achieving a high-quality compressed pulse with higher compression factor.