PhD in Optical fibre sensing for ultra-high-pressure rheometry

1 - Working at the VUB

For more than 50 years, the Vrije Universiteit Brussel has stood for freedom, equality and solidarity, and this is very much alive on our campuses among students and staff alike. 

At the VUB, you will find a diverse collection of personalities: innovators pur sang, but above all people who are 100% their authentic selves. With some 4,000 employees, we are the largest Dutch-speaking employer, in the private sector, in Brussels; an international city with which we are only too happy to connect and where (around) our 4 campuses are located. 

Add to this our principle of free research - in which self-reflection, a critical attitude and an open, creative mind around scientific and social issues are central - and you have a university that is fundamentally groundbreaking and pioneering in education and research. In short: the VUB all over again. 

Moreover, the VUB is a member of EUTOPIA, an alliance of like-minded European universities, all ready to reinvent themselves.

2 - Position description

The Faculty of Engineering, Department Toegepaste natuurkunde en fotonica, Research Group Brussels Photonics is looking for a PhD-student with a doctoral grant. 

More concretely your work package, for the preparation of a doctorate, contains: 

Your work will be an essential part of the RheoLub research project, funded by the Research Foundation - Flanders (FWO). The project aims to develop advanced experimental and modelling methods to better understand the behaviour of industrial lubricants under extreme operating conditions. Lubricants in gears, bearings and other mechanical systems can be exposed to very high pressures and temperatures, as well as high shear rates. Reliable measurements under such conditions are essential for the design of efficient, durable and electrified machinery, yet current measurement techniques have significant limitations.

Within RheoLub, the VUB team at Brussels Photonics - B-PHOT (www.b-phot.org) will focus on the development of optical fibre sensing technologies. The objective is to develop and validate miniature fibre-optic sensors capable of measuring pressure and temperature in a new generation of ultra-high-pressure rheometers. The intended application is a slit-die rheometer cartridge in which optical fibres are integrated close to the lubricant flow channel. This will enable spatially resolved measurements of pressure and temperature profiles under extreme operating conditions.

As a PhD researcher, your work will specifically involve the following activities:

• Designing and numerically evaluating strategies for integrating optical fibre sensors into high-pressure environments, taking into account parameters such as fibre type, coating, groove geometry, embedding depth, bonding layer and host material.
• Developing and integrating arrays of Fiber Bragg Grating (FBG) sensors in standard single-mode and/or microstructured optical fibres for spatially resolved pressure and temperature measurements.
  Investigating pressure-sensitive fibre concepts, including the Butterfly microstructured optical fibre developed at VUB, as well as sensing approaches based on birefringence.
• Experimentally calibrating the developed sensors in dedicated high-pressure test setups, including the analysis of pressure and temperature cross-sensitivity.
• Developing methods for processing spectral measurement data, including Bragg peak tracking, peak-shape analysis, analysis of birefringence-induced peak splitting, temperature compensation, and the conversion of strain into pressure.
• Integrating and validating the optical fibre sensors in close collaboration with the project partners at Ghent University, who are responsible for developing the rheometer cartridge, thin-film sensors as a reference technology, and methods for extracting material properties based on digital twins.
• Communicating research results through scientific publications, project meetings and international conferences.

Depending on your profile, the position may, in addition to the research activities, involve a limited amount of teaching-related duties, such as supervising practical sessions and exercise classes and/or supervising Master’s thesis students. Such teaching activities will always be of very limited scope and will be coordinated with your research programme and progress towards the PhD.

You will join the B-PHOT research group at VUB and will be supervised by Prof. Francis Berghmans and Dr Sidney Goossens. The position involves close collaboration with project partners at Ghent University, whose research focuses on ultra-high-pressure rheometry, tribology and the modelling of lubricants.

Your main workplace will be the Brussels Humanities, Sciences & Engineering Campus in Etterbeek. Depending on the experimental activities, project collaborations and project meetings, you will also regularly work at our Photonics Innovation Center in Pajottegem.

3 - Profile

What do we expect from you?

• Master’s degree in engineering, physics, photonics, applied physics, electrical engineering, mechanical engineering, materials science, or a related scientific discipline.

  Candidates who have not yet completed their Master’s degree are welcome to apply and participate in the selection procedure. They must provide proof of enrolment in a Master’s programme and fulfil all degree requirements before the start of their appointment at VUB.

• You have a strong interest in photonic sensing systems, optical fibre technology and experimental research in challenging environments.
• Demonstrable knowledge of photonics, fibre optics, Fiber Bragg Gratings (FBGs), optical sensing technology, signal processing and/or experimental optics is required.
• Experience with MATLAB, Python, LabVIEW or similar programming environments is a strong asset.
• Experience with COMSOL Multiphysics, finite-element modelling, optomechanical simulations and/or mechanical design is an advantage.
• Experience with experimental optical setups and equipment, such as optical fibre sensors, fibre-optic interrogators, optical spectrum analysers, laser drivers or amplifiers, is an advantage.
• Experience with sensor integration, adhesive bonding, coatings, high-pressure testing, data acquisition or instrumentation is an additional asset.
• You are expected to be able to conduct research independently and critically, demonstrate excellent communication skills, and work constructively as part of a team.
• Strong planning and time-management skills are essential, as is the ability to meet deadlines and work efficiently within a multidisciplinary research project.
• A good command of spoken and written English is required. If necessary, you will have the opportunity to attend evening English classes to further improve their language skills.
• You must be willing to travel within Europe and, where necessary, beyond Europe to attend international conferences, project meetings and research stays at partner institutions.

• You have not performed any works in the execution of a mandate as an assistant, paid from operating resources, over a total (cumulated) period of more than 12 months.

• As a (non-)EEA national, meet the conditions for obtaining a valid permit for VUB and comply with the VUB residence requirements. More info here.

The VUB wants to be a reflection of the society where everyone's talent is valued, regardless of gender, age, religion, skin color, migration background, disability and neurodiversity.

4 - Offer

Are you going to be our new colleague?

You’ll be offered a full-time PhD-scholarship, for 12 months (extendable up to max. 48 months, on condition of the positive evaluation of the PhD activities), with planned starting date 01/01/2027. 

You’ll receive a grant linked to one of the scales set by the government.

IMPORTANT: The effective result of the doctorate scholarship is subject to the condition precedent of your enrolment as a doctorate student at the university.

At the VUB, you’re guaranteed an open, involved and diverse workplace where you are offered opportunities to (further) build on your career.

As well as this, you will also enjoy various other benefits:

• Extensive homeworking options, a telework allowance of 50 euros per month OR an internet fee of 20 euros per month;
• An open and informal working environment where attention is paid to work-life balance, and exceptional holiday arrangements with 35 days of leave (based on a fulltime contract), closure between Christmas and New Year and 3 extra leave days;
• Cost-free hospitalisation insurance;
• Full reimbursement of your home-to-work commute with public transport according to VUB-policy, and/or compensation if you come by bike; 
• A wide selection of meals in our campus restaurants at attractive prices;
• Excellent and affordable facilities for sport and exercise, a range of discounts via Benefits@Work (in  all kinds of shops, on flights, in petrol stations, amusement parks...) and Ecocheques; 
• Nursery near campus, discount on holiday camps; 
• The space to form your job content and to continuously learn through our VUB learning platforms and training courses;
• And finally: great colleagues with a healthy drive.

5 - Interested?

Is this the job you’ve been dreaming of?

Then apply, at the latest on 30/09/2026, via jobs.vub.be, and upload the following documents:

• your CV;
• your motivation letter;
• your diploma (not applicable for VUB alumni).

Our application process is as follows (subject to change):

• step 1: an initial selection based on your application file; 
• step 2: a job interview.

Do you have questions about the job content? Contact Sidney Goossens at sidney.goossens@vub.be.

Would you like to know what it’s like to work at the VUB? Go to jobs.vub.be, and find all there is to know about our campuses, benefits, strategic goals and your future colleagues.

Would you like more information about EUTOPIA? Go to eutopia-university.eu, and read more about the role of the VUB in the development of the EUTOPIA alliance.