Pure-quartic solitons (PQSs) with higher energy in short pulse width have been generated in the mode-locked fiber laser recently, and soliton molecules have been found as a means to improve the communication capacity of the optical fiber, which has attracted much attention. In this paper, we consider the fourth-order nonlinear Schrödinger equation (FNLSE) derived from Lakshmanan-Porsezian-Daniel equation which is describing the propagation of PQS in optical fiber systems. Through the Hirota’s bilinear method, the bilinear forms and the one- and two-PQS solutions of the FNLSE are obtained. Then, the dynamic characteristics of the PQSs are discussed by using parameter control. Besides, through the velocity resonance conditions, the static and non-static PQS molecules are obtained. Under the condition of different parameters, the dynamic characteristics of the PQS molecules transmission process are analyzed. An interesting phenomenon of the PQS molecular interaction is found. We find that under the certain conditions, the PQS molecule composed of two solitons can evolve into the stable new form. Moreover, the soliton-asymmetric soliton molecule are obtained by the parameters control.

近来，锁模光纤激光器中产生了短脉宽能量更高的纯四次孤子（PQSs），并且发现了孤子分子作为提高光纤通信容量的一种手段，备受关注。 . 在本文中，我们考虑从 Lakshmanan-Porsezian-Daniel 方程导出的四阶非线性薛定谔方程 (FNLSE)，该方程描述了光纤系统中 PQS 的传播。通过Hirota的双线性方法，得到了FNLSE的双线性形式和一、二PQS解。然后，通过使用参数控制来讨论 PQS 的动态特性。此外，通过速度共振条件，获得静态和非静态 PQS 分子。在不同参数条件下，分析了PQS分子传输过程的动态特性。发现了 PQS 分子相互作用的一个有趣现象。我们发现在一定条件下，由两个孤子组成的 PQS 分子可以演化成稳定的新形式。此外，通过参数控制得到孤子-不对称孤子分子。