Graphene photonic crystal fibre with strong and tunable light–matter interaction

The integration of photonic crystal fibre (PCF) with various functional materials has greatly expanded the application regimes of optical fibre^1–12. The emergence of graphene (Gr) has stimulated new opportunities when combined with PCF, allowing for electrical tunability, a broadband optical response and all-fibre integration ability^13–18. However, previous demonstrations have typically been limited to micrometre-sized samples, far behind the requirements of real applications at the metre-scale level. Here, we demonstrate a new hybrid material, Gr–PCF, with length up to half a metre, produced using a chemical vapour deposition method. The Gr–PCF shows a strong light–matter interaction with ~8 dB cm⁻¹ attenuation. In addition, the Gr–PCF-based electro-optic modulator demonstrates a broadband response (1,150–1,600 nm) and large modulation depth (~20 dB cm⁻¹ at 1,550 nm) under a low gate voltage of ~2 V. Our results could enable industrial-level graphene applications based on this Gr–PCF and suggest an attractive platform for two-dimensional material-PCF.