  Photonic quantum technology can be enhanced by monolithic fabrication of both
the underpinning quantum hardware and the corresponding electronics for
classical readout and control. Together, this enables miniaturisation and
mass-manufacture of small quantum devices---such as quantum communication
nodes, quantum sensors and sources of randomness---and promises the precision
and scale of fabrication required to assemble useful quantum computers. Here we
combine CMOS compatible silicon and germanium-on-silicon nano-photonics with
silicon-germanium integrated amplification electronics to improve performance
of on-chip homodyne detection of quantum light. We observe a 3 dB bandwidth of
1.7 GHz, shot-noise limited performance beyond 9 GHz and minaturise the
required footprint to 0.84 mm. We use the device to observe quantum squeezed
light, from 100 MHz to 9 GHz, generated in a lithium niobate waveguide. This
demonstrates that an all-integrated approach yields faster homodyne detectors
for quantum technology than has been achieved to-date and opens the way to
full-stack integration of photonic quantum devices.
