  Optical homodyne detection has found use in a range of quantum technologies
as both a characterisation tool and as a way to post-selectively generate
non-linearities. So far optical implementations have been limited to bulk
optics. Here we present the first homodyne detector fully integrated with
silicon photonics and suitable for measurements of the quantum state of the
electromagnetic field. This high speed, compact detector shows low noise
operation, with 10 dB of clearance between shot noise and electronic noise, up
to a speed of 160 MHz. These performances are suitable for on-chip
characterisation of optical quantum states, such as Fock or squeezed states. As
a first application, we show the generation of quantum random numbers at 1.2
Gbps generation rate. The produced random numbers pass all the statistical
tests provided by the NIST statistical test suite.

Quantum Physics