  Graphene and related materials can lead to disruptive advances in next
generation photonics and optoelectronics. The challenge is to devise growth,
transfer and fabrication protocols providing high (>5,000 cm2 V-1 s-1) mobility
devices with reliable performance at the wafer scale. Here, we present a flow
for the integration of graphene in photonics circuits. This relies on chemical
vapour deposition (CVD) of single layer graphene (SLG) matrices comprising up
to ~12000 individual single crystals (SCs), grown to match the geometrical
configuration of the devices in the photonic circuit. This is followed by a
transfer approach which guarantees coverage over ~80% of the device area, and
integrity for up to 150 mm wafers, with room temperature mobility ~5000 cm2 V-1
s-1. We use this process flow to demonstrate double SLG electro-absorption
modulators with modulation efficiency ~0.25, 0.45, 0.75, 1 dB V-1 for device
lengths ~30, 60, 90, 120 {\mu}m. The data rate is up to 20 Gbps. Encapsulation
with single-layer hBN is used to protected SLG during plasma-enhanced CVD of
Si3N4, ensuring reproducible device performance. Our full process flow (from
growth to device fabrication) enables the commercial implementation of
graphene-based photonic devices.
