Researchers from the University of Bristol have made a detector to measure quantum features of light in more detail than ever before, with a sensor “clocked at an order of magnitude faster than the previous state-of-the-art,” said Bristol.
It was used to measure the unique properties of ‘squeezed’ quantum light at record high speeds, according to the university’s Quantum Engineering Technology Lab, which worked with Université Côte d‘Azur.
“Squeezed light is a quantum effect that is very useful,” said Bristol scientist said Joel Tasker. “It can be used in quantum communications and quantum computers and has already been used by the LIGO and Virgo gravitational wave observatories to improve their sensitivity, helping to detect exotic astronomical events such as black hole mergers.”
Extremely low noise and high bandwidth was required and the sensor achieves this with two chips: CMOS-compatible silicon and germanium-on-silicon photonics with a SiGe electronic amplifier in a homodyne receiver – where the transmit signal is used as the receive local oscillator.
“Much of the focus has been on the quantum part, but now we’ve begun integrating the interface between quantum photonics and electrical readout,” said project director Professor Jonathan Matthews. “This is needed for the whole quantum architecture to work efficiently. For homodyne detection, the chip-scale approach results in a device with a tiny footprint for mass-manufacture and provides a boost in performance.”

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