Postdoctoral position (2 years) in fabrication of hollow-core optical fibers for next-generation communication

The Department of Applied Physics and Electronics currently has about 100 employees and conducts research in areas such as energy technology, laser spectroscopy, medical technology, and electronics and systems engineering. The Department is now seeking a postdoctoral researcher to develop fabrication process for making hollow-core optical fibers for future optical communication. The position is full time for two years with starting date September 1st, 2025 or according to agreement.

Project description
The Internet is enabled by a network of silica fibers with a step-index profile. Since the invention of the optical fiber 50 years ago, its design has not been radically changed. During the last 10 years, it has been discovered that a new class of hollow-core fibers (HCFs) can potentially provide several key advantages over conventional fibers, including lower propagation loss, lower latency (due to the faster speed of light in air than in glass), lower nonlinearity and dispersion, and the liberty of choosing light wavelengths in a wider spectral range. These HCFs are based on anti-resonant reflection by sub-micron-thick silica membranes. Despite breakthroughs, significant challenges remain especially in HCF fabrication. The key challenge is to maintain the uniformity of nanostructured cross-section of fiber for tens of kilometers length.

In this project, you as a postdoctoral researcher will mainly carry out:

• optimization of both fiber preform preparation and fiber drawing processes so as to reliably fabricate HCFs with desired geometrical parameters for an extended fiber length (beyond 10 km), and
• characterization of the fabricated HCFs (e.g. optical transmission properties).

Apart from the main tasks above, the postdoc can be involved in the following research area if interest arises:

• numerical simulation of thermo- and fluid dynamics under fiber-drawing processes.

HCF fabrication will be carried out at RISE Fiberlab (Hudiksvall), one of the leading specialty fiber R&D facilities in Europe. Hudiksvall is located around 4 hours away from Umeå by train. Both HCF preform preparation and fiber drawing require delicate tuning of multiple parameters, which often need to be performed manually. For each specific HCF design, an optimized fabrication process can take many iterations.  Therefore, the postdoctoral researcher will be expected to stay in Hudiksvall for extended periods during employment. Extra costs related to accommodation in Hudiksvall and transportation between Umeå and Hudiksvall under the project will be compensated.

The project is part of a consortium project supported by Vinnova (Swedish Agency for Innovation Systems) with partners including RISE High-Speed Transmission Lab (Kista, Stockholm), RISE Fiberlab (Hudiksvall), Chalmers University of Technology (Gothenburg), as well as the companies Ericsson, Telia, and Telenor.

Qualifications
To be appointed under the postdoctoral agreement, the postdoctoral fellow is required to have completed a doctoral degree or a foreign degree deemed equivalent to a doctoral degree. This qualification requirements must be fulfilled no later than at the time of the appointment decision.

To be appointed under the postdoctoral agreement, priority will be given to candidates who completed their doctoral degree no later than three years prior. If there are special reasons, candidates who completed their doctoral degree earlier may also be eligible. Special reasons include absence due to illness, parental leave, appointments of trust in trade union organisations, military service, or similar circumstances, as well as clinical practice or other forms of appointment/assignment relevant to the subject area.

Additional requirements:

• The doctoral degree should be in one of the following fields: materials engineering or science, mechanical engineering, electrical engineering, optical engineering, nanotechnology, or equivalent.
• Experience with drawing of optical fibers especially hollow-core fibers.
• Fluency in English, both in oral and written forms. 

Highly meritorious:

• Knowledge in theoretical/numerical methods for simulation of thermo- and fluid dynamics.
• Knowledge in optics.
• Ability to communicate in Swedish.

We are looking for candidates who are highly motivated, goal-oriented, capable of critical thinking, and willing to collaborate with other members in a team.

Application
A complete application should include:

1. A cover letter summarizing your qualifications, your scientific interests, your motives for applying, and how you feel you meet the essential and meriting criteria (max 2 pages);
2. Curriculum vitae (CV) with publication list;
3. Copy of doctoral degree certificate or documentation that clarifies when the degree of doctor is expected to be obtained;
4. Copy of doctoral thesis (PDF or a download link);
5. Copies of other diplomas (master and bachelor studies);
6. A list of university courses with grades (transcripts). Note that for international applicants the grading system should be explained in brief;
7. Contact information of at least two reference persons;
8. (optional) Other documents that the applicant wishes to supply.

The application, including attached documents, must be written in English or Swedish. Documents sent electronically must be in PDF format. The application is made through our electronic recruitment system Varbi. Application closing date is 16 May 2025.

Further information
For more information, please contact Max Yan (max.yan@umu.se), or head of department Britt Andersson (britt.andersson@umu.se).