Quantum Optics Engineer – Entanglement-based QKD Systems

Quantum Technologies GmbH

Quantum Optics Engineer at zerothird GmbH in Vienna focusing on entanglement-based Quantum Key Distribution systems. Hands-on experimental work in design, operation, and optimization of quantum communication systems.

Posted 5/19/2026full-timeWien • 🇦🇹 AustriaMid-LevelSenior💰 €3,284 per monthWebsite

Tech Stack

Tools & technologies

Python

About the role

Key responsibilities & impact

Design, build, align, and operate optical setups for polarization-entangled photon sources and entanglement-based QKD systems, including free-space and fiber-based implementations.
Perform detailed measurements of source brightness, entanglement quality, loss, timing, and stability; analyze results and iteratively improve system performance and robustness.
Take ownership of laboratory experiments, including optical alignment, calibration of detectors and electronics, troubleshooting of experimental issues, and documentation of setups and procedures.
Develop and maintain experiment control, data acquisition, and analysis software (e.g. for measurements, calibration routines, and long-term stability tests).
Work closely with software, electronics, and systems engineers to integrate optical subsystems into full QKD nodes and network deployments.
Contribute to the exploration and prototyping of next-generation components and concepts, including improvements to entangled photon sources and optical subsystems.

Requirements

What you’ll need

Master’s degree or PhD in Physics, Applied Physics, Quantum Optics, Photonics, or a closely related field.
Strong hands-on laboratory experience in quantum optics or photonics, including optical alignment, use of lasers, single-photon detectors, fiber optics, and standard optical instrumentation.
Familiarity with entanglement-based QKD concepts, polarization optics, and quantum state characterization is highly desirable.
Practical experience writing code for experiment control, data acquisition, or data analysis (e.g. Mathematica, Python, C/C++, or similar).
Experience with nonlinear optics (e.g. SPDC sources, crystal-based photon-pair generation).
Single-photon detection technologies and timing electronics.
Long-term stabilization of optical systems and experiments outside laboratory conditions.
Excellent command of English and/or German, both written and spoken, to ensure effective communication within a diverse team.

Benefits

Comp & perks

Vibrant Quantum Community: Join a young and dynamic team where dialogue is fostered at all levels.
Family-Friendly Workplace: zerothird values the balance between work and family life. We understand and support the needs of working parents within our team, offering flexible working arrangements, part time possibilities and a culture of mutual support where family comes first.
Exceptional Career Opportunities: As a startup at the forefront of rolling out unique quantum cryptography technologies worldwide, we offer unparalleled career growth opportunities.
Inclusive Culture: Thrive in an authentic „Duz-Kultur“ where everyone is on a first-name basis, encouraging short decision-making processes and fostering a friendly, open office environment.
Personalized Onboarding: Receive comprehensive introduction training, supported by a dedicated mentor to ensure a smooth transition and successful integration into our team.
Daily Energizers: Enjoy complimentary amenities such as soft drinks, coffee, tea, fresh fruit, and ice cream to keep you refreshed throughout the day.
Special Events: Participate in regular company activities including summer parties, and festive Christmas parties.

ATS Keywords

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Applicant Tracking System Keywords

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Hard Skills & Tools

optical setupspolarization-entangled photon sourcesentanglement-based QKD systemsoptical alignmentcalibration of detectorsdata acquisitiondata analysisMathematicaPythonC/C++

Soft Skills

ownership of laboratory experimentstroubleshootingdocumentationcollaborationcommunication

Certifications

Master’s degreePhD