Manganese dioxide (MnO₂) is a widely used and well-studied 3-dimensional (3D) transition metal oxide, which has advantages in ultrafast optics due to large specific surface area, narrow bandgap, multiple pores, superior electron transfer capability, and a wide range of light absorption. However, few studies have considered its excellent performance in ultrafast photonics. γ-MnO₂ photonics devices were fabricated based on a special dual-core, pair-hole fiber (DCPHF) carrier and applied in ultrafast optics fields for the first time. The results show that the soliton molecule with tunable temporal separation (1.84 to 2.7 ps) and 600-MHz harmonic solitons are achieved in the experiment. The result proves that this kind of photonics device has good applications in ultrafast lasers, high-performance sensors, fiber optical communications, etc., which can help expand the prospect of combining 3D materials with novel fiber for ultrafast optics device technology.