The optical fiber joint closure, also known as the optical cable splicing closure, is a sealed protection device for optical cable splicing points. It is mainly used for through and branch connections of optical cables in scenarios such as overhead, duct, and direct burial applications, integrating functions of optical fiber fusion splicing, residual fiber storage, and distribution. Constructed with durable materials like reinforced engineering plastics, it features waterproof, corrosion-resistant, and wide temperature resistance (-40℃~+80℃) properties, capable of withstanding high-intensity axial tension and impact to ensure no additional attenuation of optical fibers inside the closure. Supporting multiple reuse and capacity expansion, it is compatible with multi-core optical cables, offering convenient construction and maintenance. It is widely applied in optical cable network systems such as communications, CATV, and FTTH.