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Frequency conversion and stabilization in photonic integrated circuits

Applications are invited for a PhD fellowship/scholarship at Graduate School of Technical Sciences, Aarhus University, Denmark, within the Engineering programme. The position is available from 1 November 2020 or later.

Frequency conversion and stabilization in photonic integrated circuits

Research area and project description:
The Group of Integrated Photonics and Nonlinearities (IPN) at the Department of Engineering of Aarhus University is looking for an early-stage researcher to work on frequency conversion and stabilisation of diode lasers. Application deadline is 1 August 2020.

This PhD project will focus on the engineering of optical nonlinearities in semiconductors to design a robust and scalable laser device with high spectral purity for emission at various wavelengths. The overall aim of the project is to demonstrate a photonic technology that can be deployed outside the research lab. It targets sensing applications with improved precision, cost and power efficiency.

We will closely work together with other Photonics groups at Aarhus University and our vision is to adopt a fabless approach, thus leveraging on existing and mature foundry processes to fabricate the laser chips. This PhD topic is at the interface between laser physics, nonlinear integrated photonics, semiconductor devices and sensing. The PhD student will thus acquire an expertise in several fields of research and in a wide range of experimental techniques.


[1] Stanton, Volet, Bowers, Mirin, et al., “Efficient second harmonic generation in nanophotonic GaAs-on-insulator waveguides”, Opt. Express 28, 9521–9532 (2020).

[2] Raja, Liu, Volet, Morton, Bowers, Kippenberg, et al., “Chip-based soliton microcomb module using a hybrid semiconductor laser”, Opt. Express 28, 2714–2721 (2020).

[3] Chang, Volet, Papp, Bowers, et al., “Strong frequency conversion in heterogeneously integrated GaAs resonators”, APL Photonics 4, 036103 (2019).

[4] Stanton, Spott, Volet, Meyer, Bowers, et al., “Multi-spectral quantum cascade lasers on silicon with integrated multiplexers”, Photonics 6, 6 (2019).

[5] Spencer, Volet, Kippenberg, Vahala, Newbury, Srinivasan, Bowers, Diddams, et al., “An optical-frequency synthesizer using integrated photonics”, Nature 557, 81–85 (2018).

[6] Chang, Volet, Wang, Bowers, et al., “Thin film wavelength converters for photonic integrated circuits”, Optica 3, 531–535 (2016).

[7] Wang, Volet, Kippenberg, Bowers, et al., “Frequency comb generation in the green using silicon nitride microresonators”, Laser Photon. Rev. 10, 631–638 (2016).

The candidate must have at least a Bachelor’s degree (or equivalent) in Electrical Engineering, Physics, or related field. He/she should have a passion for experimental photonics, and should be stimulated by challenging projects. He/she should be proficient in English (written and spoken), self-driven, and scientifically curious. A background (theoretical and/or experimental) in semiconductor lasers and nonlinear optics is highly recommended. The ideal candidate will enjoy practical hands-on work and is willing to acquire new skills with a good attitude to work in a team and independently. He/she will have opportunities to work with both internal and external collaborators, and interact with global industries to showcase his/her talents to potential future employers.

The place of employment is Aarhus University, and the place of work is the Department of Engineering, Section of Electrical and Computer Engineering, Finlandsgade 22, 8200 Aarhus N, Denmark.

Applicants seeking further information are invited to contact:
Tenure-Track Assistant Professor Nicolas Volet, e-mail: volet@eng.au.dk and Associate professor Martijn Heck, e-mail: mheck@eng.au.dk

Application procedures

Before you apply

Information and attachments:

Please be aware that you must have all relevant appendices, attachments, addresses for referees, etc. ready when you apply, as the entire application must be uploaded to the system in one go.

Documentation of language skills:

The English language requirement at the graduate school is comparable to an “English B level” in the Danish upper secondary school (“gymnasium”).

English language qualifications comparable to an “English B level” are documented by one of the following tests:

  • TOEFL test (internet-based), minimum score: 83. The graduate school does not accept the paper-based test, nor the TOEFL ITP test. Remember to ask the test center to send your test results to Aarhus University in order to enable verification of your test results. Aarhus University’s TOEFL code is 8935.
    Currently, the TOEFL iBT Special Home Edition test (available in selected areas) will also be accepted.
  • IELTS (academic) test, minimum average score: 7.0 points
    Please note, from 1 June 2020 the Graduate School of Science and Technology has split in two following the split of the faculty. For the two new schools, Graduate School of Natural Sciences and Graduate School of Technical Sciences, the minimum average score requirement for an IELTS test is 7.0 points (equivalent of a C1 level).
  • Cambridge English Language Assessment:
    Cambridge Certificate of Proficiency (CPE)
    Cambridge English: Certificate of Advanced English with grade A,B or C (CAE)
    Cambridge English: First Certificate with grade A (FCE)

When to take the test and how to upload the documentation:
The test result must not be more than two years old at the time of application.

The English language test should be taken before applying for admission and uploaded under “language skills documentation” in the online application form.

It is possible to apply for admission before you have taken the test. In this case documentation stating that you have signed up for a test (please state expected submission date) must be uploaded. If the test result is not part of the original application the test result is to be sent to gsts@psys.au.dk no later than one month after the application deadline.

The following applicants are exempted from documenting their English qualifications/taking a test:

  • Applicants with citizenship from the following countries: Australia, Canada, Ireland, New Zealand, the United Kingdom, the United States, or one of the Nordic countries (Denmark, Finland, Iceland, Norway or Sweden).
  • Applicants with a Bachelor’s or Master’s programme completed in Australia, Canada, Ireland, New Zealand, the United Kingdom, or the United States. In this case, please upload your Bachelor’s or Master’s diploma under the section ”Language skills documentation”.
  • Applicants with a Bachelor’s or Master’s programme completed at a Danish university for which the requirement was English B level at the time of admission. In this case, please upload your Bachelor’s or Master’s diploma under the section ”Language skills documentation”.

The programme committee may request further information or invite the applicant to attend an interview.

How to apply:

1)      Find the application form:
Go to https://phd.tech.au.dk/for-applicants/apply-here/ - Note, the online application system opens on 1 June 2020.
Choose August 2020 Call with deadline 1 August 2020 at noon (11.59 AM CEST).
You will be directed to the call, and must choose the programme “Engineering”.

2)      Fill in the following information:

  • Personal information
  • Academic background
  • Admission
  • Financing (if any)
  • Study: In the dropdown menu you must choose the project: “Frequency conversion and stabilization in photonic integrated circuits”
  • Source (how you found out about the call)

Next to some of the information fields you will find a number. Click on the number to get further directions on how to fill in the information field/what information is needed.

3)      Application attachments:
Please be aware that you cannot submit the application if one or several of these documents have not been uploaded.

If you wish to upload more than one document under each section, you must scan/merge all documents into one large PDF file and upload this. Please note that we reserve the right to remove scientific papers, large reports, theses and the like. Instead you can indicate a URL where the information is available.

All information in the application must be in English or Danish, preferably English. A certified English translation is required for documents written in languages other than English or one of the Scandinavian languages (i.e. Norwegian, Swedish or Danish) languages.

As a minimum all applications must include (pdf-files only, max. 20 MB, no zip):

  • One reference (template for references)
  • Curriculum vitae,
  • Motivation (max. 1 page)
  • Transcripts, grade point averages (weighted and unweighted), and diploma(s) for both Bachelor’s and Master’s degree. If the original documents are not in English or one of the Scandinavian languages (i.e. Norwegian, Swedish or Danish) then copies of the original documents as well as a certified English translation must be attached.
  • Project description (½-4 pages). For technical reasons, you must upload a project description. When - as here - you apply for a specific project, please simply copy the project description above, and upload it as a PDF in the application. If you wish to, you can indicate an URL where further information can be found. Please note that we reserve the right to remove scientific papers, large reports, theses and the like.
  • Documentation of language skills if required.

After submission of the application, you will receive a confirmation e-mail with an application ID, you should use for reference if needed.

The graduate school reserves the right to verify the authenticity of your educational diploma and transcripts:

  • Request additional information to verify an application.
  • Reject the application if it is proven, or if the University has reasonable belief, that the information provided is false or if the applicant refuses to provide the requested information, whether or not an offer has already been made. 
  • For further information on applying, assessment procedures, etc. please see the GSTS Application Guide.

Please note:

  • The programme committee may request further information or invite the applicant to attend an interview.
  • The project will only be initiated if final funding (from the graduate school/the faculty) is secured.

All interested candidates are encouraged to apply, regardless of their personal background.

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