Fibre side-polishing technology was explored to meet the need for miniature, multifunctional, and low-loss device platforms for optical applications. Different polishing techniques were investigated to achieve side-polished fibres with low transmission loss, high polished surface quality and long interaction lengths. This side-polished fibre platform was combined with some of the most popular two-dimensional materials, including graphene and molybdenum disulfide, to fabricate integrated optical fibre devices. A high refractive index polyvinyl butyral layer was coated on top of graphene and molybdenum disulfide to enhance the light-matter interaction between the evanescent field of the core guided mode and the two-dimensional materials. By using the excellent photonic properties of graphene, a broadband graphene-based fibre polariser was proposed and fabricated using the low-loss side-polished optical fibre platform. Characterisation of the optical properties revealed that the graphene-based polariser retains low transmission losses and high extinction ratios across an extended telecoms band. The graphene-based fibre device was also utilized to demonstrate a high-speed, in-fibre optical modulator, which realised fast modulation speed and high modulation depth. By using the same design, a low-loss molybdenum disulfide-based all-optical modulator was also demonstrated with a even higher modulation depth. Wavelength-dependent interaction and spectral broadening was observed in the molybdenum disulfide sheet, suggesting that the higher modulation depth was from a resonance-enhanced interaction. To extend the application scenarios of the side-polishing technique, a low loss, wideband multi-core to single-mode fibre coupler was also demonstrated. The coupler was designed to access light from a single core of the multi-core fibre without disrupting the signal propagation in the remaining cores. The coupling ratio between the two fibres could be continuously tuned over the entire spectral band via a simple mechanical displacement method.