Hollow core fibres guide light using the principle of total internal reflection (TIR), where light rays propagating along the core undergo near 100% reflection at the core-cladding boundary. To achieve this, the cladding must have an effective refractive index below that of. For decades, optical fibers have relied on a solid glass core to guide light and have formed the backbone of global telecommunications. However, glass imposes a fundamental physical limitation because light travels through it approximately 30 percent slower than through air. Compared to solid-core optical fibers, HCFs exhibit ultra-low nonlinearity, high damage threshold, low latency and temperature. We report the fabrication and characterisation of a multi-core anti-resonant hollow core fibre with low inter-core coupling. This new type of cable propels light through a central channel filled with air or a vacuum, fundamentally changing the interaction between the.
