Dr Loyd McKnight

Theme Leader- Quantum Tech

Quantum Techologies

Photonics role in QT

Photonics is an underpinning technology for many quantum applications which places

stringent requirements on both laser sources and optical systems. Fraunhofer CAP has a

track record as a delivery partner in meeting these challenges.

Fraunhofer CAP has played a key technology translation role in many collaborative QT

projects funded within the UK quantum initiative and beyond. Industrial partners range

from laser manufacturers to large aerospace and defence organisations. Projects range

from laser development to the realisation of complete systems incorporating cold atoms.

 In addition, Fraunhofer CAP is well placed to participate in European level projects.



Quantum applications frequently demand precise wavelength and linewidth stabilisation

amongst other tightly controlled characteristics. This is an area where Fraunhofer CAP

has developed extensive experience in both design and characterisation. Fraunhofer

CAP expertise in this field is not restricted to sources and includes working alongside our

commercial partners on the development of complete systems for the practical application

of quantum technology for example in the sensing of, position, gravity and magnetic fields.


Fraunhofer CAP Expertise includes but is not limited to:

  • Narrow linewidth lasers and their characterisation
  • Complete system design
  • Locking and stabilisation of laser sources
  • Reduced Size Weight and Power of laser systems
  • Mechanical design for robust performance
  • Frequency conversion
  • Cold atom systems
  • Quantum photon sources
  • Quantum enhancement of sensing
  • Low photon count sensing

Industrial Strategy Challenge Fund projects:

Fraunhofer CAP is participating it two of InnovateUK's four largest QT projects


Pioneer Gravity: Gravity sensors  for infrastructure productivity, situational awareness and seeing the invisible

Despite our increasing ability to detect and monitor objects that exist on land, sea, around buildings or in space, our ability to detect objects beneath the ground has not improved significantly. When it comes to attempting to locate a buried and forgotten pipe, telling the extent of a sink hole or assessing the quality of infrastructure we still often resort to digging or drilling holes. This presents a huge economic and societal cost as road networks are dug up, oil wells are dry or brown-field land is left undeveloped. Existing techniques are all fundamentally limited in either their sensitivity (classical microgravity), their penetration (Ground Penetrating Radar) or their cost (seismic).

For over 30 years, universities and academics have been exploiting the strange effects of quantum superposition to measure gravity with astonishing sensitivity. Using a process called cold-atom interferometry, the wave-partial duality of a rubidium atom is compared to the phase of a laser beam in a way which can detect very small changes in the way atoms fall freely in a vacuum. Changes in this free-fall can be used to determine the local strength of gravity and if this measurement is sensitive enough, the measurement can be used to tell whether there are voids, pipes, tunnels, oil and gas reserves in the ground beneath your feet.

Although the potential is there, there are huge scientific and engineering challenges to delivering this performance.

This project is proposed by the UK consortium of the best scientific and engineering companies the UK has to offer. Working with leading UK universities, these companies are looking to overcome these challenges, and develop a new industry of 'quantum' cold-atom sensors in the UK. If these advanced performances can be demonstrated, the economic and societal benefit of this new 'quantum' industry in the UK is expected to be significant and long-lasting.

3QN: Towards A New UK Industry for Novel Quantum Receivers in Nascent Satellite QKD Global Markets         

Quantum Key Distribution (QKD) is a well understood application of quantum technology and there are several metropolitan fibre networks already established for QKD services. However, key distribution is limited by absorption inside optical fibres which mean that transmissions over distances greater than about 150 km are impractical. Free space communications, though, does not suffer the same degree of attenuation and single photon communication with satellites orbiting the Earth at several hundred kilometres has been demonstrated. Satellites then, provide an ideal vehicle for distributing quantum key information across very large distances between end users spread across countries or continents. However, in order to benefit from the advances in satellite technology, a network of Optical Ground Receivers (OGRs) are required to receive and detect the photons carrying the key information. The UK, as a major player in the development of advanced optical & photonic technologies, is well positioned to address this future market for OGR. This project works with users to specify OGR requirements and prototypes and tests a QKD receiver, whilst designing and making plans for scaled manufacture in the UK.