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Douwe Geuzebroek (promotion date: 28 october 2005)

Flexible optical network components based on densely integrated micro ring resonators.

Promotion Date: 28 October 2005

Douwe Geuzebroek

It is about integrated optics, meaning that we try to make chips that are not based on an electrical currents but on the guiding of light. A micro ring is a component of such an optical chip. The challenge is to bring the advantages of the bandwidth of glass fibre into peoples’ homes by means of cheap circuits interconnecting the existing glass fibre networks. As yet these circuits are too expensive and not very reliable or flexible. NAIS is a big European project in which groups of material development, device development and tool (calculation software) participate and collaborate to achieve this goal. My research dealt with multiple micro ring components to make cheap and reliable structures.

What was your thesis about?

It is about integrated optics, meaning that we try to make chips that are not based on an electrical currents but on the guiding of light. A micro ring is a component of such an optical chip. The challenge is to bring the advantages of the bandwidth of glass fibre into peoples’ homes by means of cheap circuits interconnecting the existing glass fibre networks. As yet these circuits are too expensive and not very reliable or flexible. NAIS is a big European project in which groups of material development, device development and tool (calculation software) participate and collaborate to achieve this goal. My research dealt with multiple micro ring components to make cheap and reliable structures.

But a micro ring is an existing optical structure?

Yes, a micro ring in itself is not new. Light is guided into the ring, circles around and builds up in intensity. This is the original purpose of the micro ring. But we use the physical properties of both the wave length of light (the colour of light) and the ring itself as a circuit.

It turns out that the demands to optimize a micro ring used as a circuit or a filter are very different from the original physical purpose of building up the intensity of light.

And besides, there is a lot of theory about micro rings, but making one is a different kettle of fish. There are only a few groups in the world that actually make them. I think that we are one of the four.

Do you communicate with these other groups?

Yes, within the NAIS framework we had a conference together. The differences in approach were very interesting. Here we have concentrated on the filter function, deploying more than one ring in a device instead of making one ring perfect, which is hardly feasible because they are so small. Our approach of a design with more than one ring has resulted in reliable and cheap devices, which is of course the ultimate aim. My rings filter 40 Gigabit of data per second. (10,000 times faster than the conventional devices).

So what you are doing is commercially very interesting?

Yes, an increase of interest is noticeable. After the burst of the Internet/telecom bubble in 2000/2001 during which time enormous amounts of money were paid for devices comparable with castles in the air, nothing at all happened in the field of micro rings. Now you see a careful explorative come-back, there is decidedly a new interest. I had an invited talk in Glasgow where you could feel the market pull.

So at the moment I am writing a business plan with the MESA spin-off Lionix to investigate the commercial possibilities.

Were you successful from the start?

The first three quarter of a year there was nobody who could build these devices, so I concentrated on the design and the network side of things. Later I picked up a close collaboration with Edwin Klein, who did quite a bit on the connecting part of between network and rings. You will find parts of his theses overlapping with mine.

Did you take steps to protect your design?

It is not possible to patent the micro rings, that’ s existing technology. But a Lionix patent is pending for the wave guide.

At the moment you work for Lionix?

Yes, via the university. We are exploring the market, which is world wide, so there is also an American consultant working on it. It is all very exciting. I enjoyed doing research, but management aspects of new technology really appeals to me.