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PhD positions - Optical interconnects and laser dynamics for wavelength division multiplexing

PhD positions in Photonics - Optical interconnects and laser dynamics for wavelength division multiplexing

Most of today’s commercial short-reach optical interconnects employ Vertical-Cavity Surface-Emitting Lasers (VCSELs) thanks to their low cost, small footprint, and large-scale fabrication capability. However, to cope with the ever-increasing demand for higher capacity, dense wavelength division multiplexing (DWDM) based on VCSELs is highly desirable but remains a challenge.

In this joint research project between the Vrije Universiteit Brussel (VUB) and Ghent University (UGent) funded by the Research Foundation – Flanders (FWO), we will investigate a scalable VCSEL-based DWDM solution combining tailored diffractive optical elements, stress-controlled VCSELs, and on-chip optical frequency comb generator. The goal is to make a proof-of-concept demonstration of this unique approach to demonstrate its feasibility. We are therefore looking for two excellent PhD candidates in photonics (duration = 48 months) to join our team.

Position Description

The work will be carried out in parallel by two PhD researchers: one is expected to primarily focus on the VCSEL investigation while the other would focus on the interconnect part of the work. Naturally, a strong collaboration between the two researchers will be required to successfully achieve the goals of the project.

Because this is a joint project between VUB (B-PHOT) and UGent (CMST), the two PhD candidates will be affiliated to both VUB and UGent in the frame of a joint PhD agreement between the two universities. In practice, the candidate focusing on the VCSEL part will be principally working at VUB while the other candidate, focusing on optical interconnect, will mainly work at UGent. Nevertheless, traveling between campuses of both universities will be regularly required.

The research work will include the following:

  • Integration of VCSEL chips on a flexible polymer substrate exploiting the unique integration process developed at UGent.
  • In-depth theoretical and experimental exploration of the effect of stress on the emission properties of VCSELs including its polarization dynamics.
  • Investigation of the injection locking properties of a stressed VCSEL when subject to injection of an optical frequency comb.
  • Design, optimization and fabrication of the diffractive optical elements and tapers by two-photon polymerization.
  • Design and fabrication of a 3D glass interposer for coupling of the different devices in a single demonstrator.

The appointment starts preferably on October 1st, 2021. The duration of the PhD position is 4 years, at the end of which the student is expected to complete his or her PhD.

Additional information

The candidate focusing on the VCSEL part will be mainly located on the VUB Humanities, Science and Engineering campus, Pleinlaan 2, 1050 Brussels, Belgium which is easily accessible by public transports, bike or car.

The candidate focusing on optical interconnect part will be mainly located on the UGent Technologiepark 126, 9052 Zwijnaarde, Belgium with the two-photon polymerization work taking place at the VUB Photonics campus in Gooik which is accessible by car, bike or train with a shuttle service organized by VUB BPHOT starting from the Edingen/Enghien train station.

At both VUB and UGent, your days will be spent in a dynamic, diverse, and multilingual environment. As an employee of the Vrije Universiteit Brussel and Ghent University, you will receive an attractive salary corresponding to one of the pay scales laid down by the government, depending on your experience and academic merits. Hospitalization insurance and free use of public transport for travel to and from work are standard conditions of employment. If you would rather cycle to work, compensation is also available for that.


  • Candidates should possess a master’s degree in Physics, Engineering or a related scientific field.
  • Good knowledge of photonics, optical physics, optical interconnects, optical communications and laser physics is required.
  • Good programming skills are a strong plus. Experience with Matlab, Scilab, R, Python or a similar language and environment is a plus.
  • Good knowledge of numerical techniques and simulation methods is a strong plus.
  • Experience with experimental optical setup and equipment such as optical spectrum analysers, laser drivers or amplifiers is a plus.
  • Experience working in a clean room and on manufacturing processes is a strong plus.
  • The candidates are expected to be able to carry out the research activities independently and in a critical manner, whilst having excellent communication skills and a positive attitude towards collaboration.
  • Good time management skills are a must, along with the ability to meet tight deadlines and work efficiently under pressure.
  • Proficiency in both spoken and written English (typically CEFR level C1 or equivalent) is required. The candidates will have the opportunity to take evening English classes to improve their language skills if needed.
  • The candidates should be prepared to travel between the VUB and UGent facilities on a regular basis. The candidates should also be willing to travel in Europe and potentially worldwide e.g. for participation in conferences or research stays at partner institutions.

Candidates that have not yet acquired their master’s degree can apply and participate in the selection procedure, but need to offer proof of registration in their Masters's programme and need to have complied with all diploma requirements before starting their position. The available PhD positions have a normal duration of 4 years in Belgium. The candidates are expected to endorse the educational vision of the universities (full text available on the university website). Both VUB and UGent are dedicated to promoting the role of women in science, and, we, therefore, explicitly invite women to apply.


For more information, please contact Prof. Martin Virte or Prof. Jürgen Van Erps.

To apply, please send your detailed CV (including a copy of the Master diploma and a Transcript of records), letters of recommendation, any supporting documents demonstrating technical skills (theses or scientific papers), and an application letter to Prof. G. Van Steenberge ( and Prof. M. Virte ( by e-mail before June 15th, 2021.

The selection process will take place in two steps: First, the file of each applicant will be carefully screened and reviewed. Well-suited candidates will be selected on this basis. Second, selected candidates will be invited to a teleconference interview during which they will be asked a broad set of technical and non-technical questions. Finally, all retained candidates will be ranked based on their academic records and their interview, and the candidates ranked 1st and 2nd will be offered the positions.

If your application is selected based on the CV and accompanying documents, you will be invited for a teleconference interview and online tests.

If no suitable candidate has been found after the deadline, the position will remain open until it is filled.

The appointment starts preferably on October 1st, 2021. The duration of the PhD position is 4 years, at the end of which the student is expected to complete his or her PhD.

Deadline: June 15, 2021

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