摘要： Anti-resonant fibres (ARFs) are of significant interest for state of the art photonic technologies. Mode guidance is largely confined to the air core, demonstrating very low optical losses [1]. Furthermore, their internal structure offers a large surface area and is thus ideal as a deposition template for the addition of novel functional materials which would be able to alter their waveguide properties. We have previously demonstrated that the deposition of thin silicon layers onto the inner regions of an ARF results in strong light-matter interaction [2]. In this work, we utilise this interaction to externally control the optical properties of the composite material ARF (CM-ARF). Here, 2D layers of MoS2 were deposited on the inner (cladding) regions of the ARF as shown in Fig. 1(a). MoS2 is a Transition Metal Dichalcogenide (TMDC) 2D material that exhibits many optoelectronic phenomena such as the electro-absorptive effect [3]. Although there are already a number of examples in which TMDCs are incorporated into optical fibre systems to exploit the third order optical nonlinearity of the material to create saturable absorbers [4], this requires large amounts of power to be absorbed by the film, which is usually placed on the end face of a fibre. In contrast, here we show clear modulation at very low power.