Defence of dissertation in the field of Optoelectronics and Photonics, M.Sc.(Tech.) John-Olof Rönn

The title of thesis is “Atomic layer deposition of erbium-doped thin films for silicon integrated waveguide amplifiers”

Data-transmitting light signal gets power boost from nanosized amplifier

Light is a more energy efficient and faster way of transferring data than electricity. Until now, the rapid attenuation of light signals in microchips has prevented the use of light as a source of an information signal. With international collaboration, this thesis has developed a nanosized amplifier to help light signals propagate through microchips. The thesis shows that the signal attenuation can be significantly reduced when data is transferred inside a microchip, for example, from one processor to another.

The breakthrough was made with the help of a Finnish invention: the atomic layer deposition method. According to thesis, the method is ideal for processing various kinds of microcircuits, as it plays an important role in manufacturing today's microprocessors. So far, the atomic layer deposition method has been used mainly in electronic applications. However, the study conducted in the thesis indicates that possible applications also exist in photonics.

In the development of photonics, new components must also ideally work with electricity - that is, in electronics. Silicon is a key material in electronics, and that's why it's also included in the light amplifiers together with the amplification element erbium. There are no compatibility issues between silicon and erbium, which is extremely beneficial when it comes to mass production.

Opponent: Professor Franz Kärtner, University of  Hamburg, Germany

Custos: Professor Zhipei Sun, Aalto University School of Electrical Engineering, Department of Electronics and Nanoengineering

Thesis web page

Contact information: John-Olof Rönn, Aalto University School of Electrical Engineering, Department of Electronics and Nanoengineering, [email protected], +358503549262

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