1. Introduction
Recently, Bessel-like beams generated by the optical fibers-based method are desirable, which is because they could offer a compact, robust, and alignment-free operation compared with bulky optical systems. So far, there are many fiber-based methods for generating Bessel-like beams, such as fiber microaxicons[1–3], self-growing micro-tips[4], or a tapered hollow tube[5]. Another way is utilizing a long-period grating to excite higher-order cladding mode and then generate Bessel beams with controllable diffraction-resistant distance[6]. These non-diffracting Bessel-like beams have attracted increasing interest owing to their unique light intensity distributions and self-healing propagation properties, which have been widely used in various domains such as optical trapping[7] and manipulation[8], high-order harmonic generation[9], nonlinear optics[10], and material processing[11]. Especially, such properties can also be used in optical wireless communication to overcome the diffraction limits and particle scattering[12], even if encountering opaque obstacles.