Optical Quantum Technologies

The New Art of Seeing and Communicating

Optical Quantum Technologies at Fraunhofer IOF

The Fraunhofer IOF is a pioneer in the field of applied research for optical quantum technologies. It offers innovative solutions for applications in science and industry wherever quantum-technological systems have the potential to enable revolutionary applications. These can be, for example, tap-proof quantum communication, low-noise quantum imaging or advanced ion traps for quantum computers. The Fraunhofer IOF is able to integrate, miniaturize and optimize systems for this purpose. Our competencies cover the entire quantum photonic process chain from modeling to system production - from basic physics to ready-to-use prototypes.

Depending on the area of ​​application, we offer our customers individually flexible solutions. In the field of quantum communication, this ranges from space-capable high-performance sources for entangled photons, to complete photonic system solutions based on adaptive optics, to lightweight telescopes for space and ground systems.

Assembly of an entangled photon source for use in Earth orbit.
Assembly of an entangled photon source for use in Earth orbit.

As the coordinator of the Fraunhofer-Leitprojekt QUILT, the Fraunhofer IOF also has outstanding expertise in quantum imaging. We develop high-power sources for photon pairs with the widest possible wavelength spread and wavelengths from the infrared to the ultraviolet range. Our system solutions open up new application fields in low-light imaging as well as in previously untapped wavelength ranges and expand the portfolio of microscopic and telescopic imaging methods.


Our portfolio of quantum photonics includes the following application areas:

  • Measurable tap-proof optical communication
  • Microscopy in undeveloped wavelength ranges
  • Optical imaging with minimal radiation dosage
  • Images and spectral analysis of scattering media, such as tissue, smoke or complex mixtures
  • Scaling of quantum computers
Quantum Imaging based on entangled photon pairs
© Fraunhofer IOF
Quantum Imaging based on entangled photon pairs

Selected projects:

Entangled photon source for tap-proof quantum communication

Scientists at the Fraunhofer Institute for Applied Optics and Precision Engineering in Jena have developed a stable, space-suitable source for entangled photons. Such connected or "entangled" photons should in future be used in secure encryption technologies (such as in so-called "Quantum Key Distribution", or QKD for short). In the photon source, a nonlinear, periodically poled crystal (ppKTP) is pumped from two sides in the arrangement of a Sagnac interferometer. The resulting spontaneous parametric fluorescence (Spontaneous Down Conversion, SPDC) in the crystal generates polarization-entangled photons in the transmitter and receiver channels. The source is under continuous development and is one of the most powerful hardware solutions in quantum communication.

Further information about the entangled photon pair source

© Fraunhofer IOF
© Fraunhofer IOF
© Fraunhofer IOF

As part of the QuNET initiative, the first quantum-secured videoconference between the Federal Ministry of Education and Research (BMBF) and the Federal Ministry for Information Security (BSI) was demonstrated in Bonn in August 2021.

Also included: a further development of the entangled photon source.

The focus of the QuNET work is the so-called "quantum key exchange", also known as QKD (short for "Quantum Key Distribution"). QKD enables the exchange of symmetric keys whose security can be quantified. The BSI is supporting the QuNET initiative and is preparing accompanying and independent test criteria in international cooperation.

Further information on QuNET and the technologies used
Press release: First quantum-secured videoconference between two federal authorities

The operating principle of the entangled photon source for quantum communication

Quantum imaging for the medical domain

Fraunhofer scientists have now developed a new method allowing light-sensitive samples to be observed for a longer time period with higher resolution. This technology is particularly relevant for the field of life sciences, since it allows to image tissue with particularly high contrast and information, without damaging or even destroying cells. This is made possible by quantum technology. Using a so-called "single crystal set up", the scientists were able to generate quantum images and videos.

The advantages of quantum physics for imaging applications are being investigated at the Fraunhofer IOF as part of the QUILT (Quantum Methods for Advanced Imaging Solutions) project.

Laboratory setup for generating quantum images.
© Fraunhofer IOF
Quantum Imaging Setup: This robust one-crystal setup allows you to examine an object in ultraviolet (UV) or infrared (IR) with simultaneous detection in the sensitivity range (VIS) of advanced silicon technology. Central to this quantum technological application is a special crystal, which allows the generation of two entangled photons at different wavelengths (UV, VIS).
Image of the happy-face template.
© Fraunhofer IOF
First test object for quantum imaging with "undetected light": An amplitude mask in the form of a happy face serves as the first examination object to demonstrate the scheme of quantum imaging technology. The happy face is illuminated with light of a certain wavelength 1.
Representation of the quantum image of the Happy Face
© Fraunhofer IOF
Quantum image of the amplitude mask in the form of a happy face. The image is generated on a camera with light of a specific wavelength 2, which differs significantly from the illumination light. Nevertheless, due to the entanglement of the two light rays (Einstein's "spooky action at a distance"), the image is visible on the camera. It is also possible to map phase objects.

The operating principle of quantum imaging