+++ At DLR, we are always looking for bright minds – even during the current exceptional circumstances. Our current vacancies can be found here. +++

Researcher at DLR. Because I am who I am.

Course paper / final thesis

Characterization of photon background in satellite-based Quantum Key Distribution

Starting date

15 April 2021

Duration of contract

3-6 months


up to German TVöD 5

Type of employment


The novel field of quantum information is promising to revolutionize many aspects of society. Particularly interesting is the possibility of realizing unconditionally secure communications via Quantum Key Distribution: this is a cryptographic primitive that does not rely on any computational assumption, as is standard in present-day cryptography, but whose security is instead guaranteed by the laws of quantum mechanics. A major hurdle to the deployment of QKD is that the intensity of a laser signal decreases exponentially along an optical fiber, limiting the maximum distance at which a optical-fiber QKD link can be established to a few hundreds of kilometers at most. A currently available technological solution to this problem is to use a satellite link instead, exploiting the fact that photons propagate without losses in the space above the atmosphere. The DLR Institute of Communications and Navigation works in the field of optical quantum and classical satellite communications. Currently, the Institute launched a cubesat to test classical communications systems between LEO and ground, the mission called PIXL-1. Future missions shall use the developed laser terminal technology to bring a QKD satellite into orbit.

The aim of the thesis is to characterize the impact of background photons on the quality of the QKD link. In fact, the receiver telescope used for the free-space quantum communication collects photons that are scattered by the satellite and by the atmosphere, resulting in an increased noise in the quantum communication. A preliminary study should investigate which QKD protocols are most resilient to noise and what amount of background photons is to be expected in different scenarios, for instance during daytime or by night. Subsequently, on-the-field measurements of the background photons should be performed and the effectiveness of techniques aiming at rejecting background photons assessed.

Your qualifications:

  • study of Electrical Engineering, Communication Engineering, Experimental Physics or similar
  • hands-on experience with optical laboratory setups
  • prior knowledge of QKD basics or of free-space optical communication is advantageous

Your benefits:

Look forward to a fulfilling job with an employer who appreciates your commitment and supports your personal and professional development. Our unique infrastructure offers you a working environment in which you have unparalleled scope to develop your creative ideas and accomplish your professional objectives. Our human resources policy places great value on a healthy family and work-life-balance as well as equal opportunities for persons of all genders (f/m/x). Individuals with disabilities will be given preferential consideration in the event their qualifications are equivalent to those of other candidates.

  • Apply online now
  • You can send this job advertisement via e-mail and complete your application on a personal computer or laptop.

    We need your digital application documents (PDF). The document upload function is not supported by all mobile devices. Please complete your application on a PC/laptop.

    Complete application on PC

Technical contact

Dr. Davide Orsucci
Institute of Communications and Navigation

Phone: +49 8153 28-4273

Send message

Vacancy 55281

HR department Oberpfaffenhofen

Send message

DLR site Oberpfaffenhofen

To location

DLR Institute of Communications and Navigation

To institute