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Graphene is a suitable material for optoelectronic applications that reveals several advantages and complementarities compared with other technologies. Graphene is a gapless material that absorbs radiation from visible to far-infrared and beyond including the terahertz range. The absorption can be modified by changing the material doping, i.e. Fermi level energy, by applying an external electric field. The change in absorption can be very fast and, for this reason, graphene can be used to realize optical modulators. Moreover, the absorption change occurs along with refractive index change. In particular, conditions, i.e. for Fermi level above the Pauli blocking, light is not absorbed anymore and only phase change occurs. Phase change has been demonstrated to be good for fast Mach Zehnder interferometer based modulation. The broadband absorption of Graphene is also exploited to realize efficient photodetectors. Generation of hot electrons upon light absorption in graphene is the cause of photo-thermal effect (PTE) that leads to photo voltage generation. PTE is an ultrafast process that is used for fast photodetection. In this work, the vision for graphene-based integrated photonics is presented. We review state-of-the-art graphene-based modulators and detectors and outline a roadmap matching the technology readiness requirements with the datacom and telecom market demands. We show that graphene-based integrated photonics could enable ultra-high spatial density, low power consumption for board and intra- data centre connectivity, access networks, metropolitan, core, regional and long-haul optical communications.
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