Mode division multiplexing for optical backplane applications

Problem Definition:

Optical interconnects are being used for shorter and shorter distances, and the first (near)commercial demonstrations of optical transmission over the back plane of computing systems are starting to appear. However, there is an increasing discrepancy between work on very high capacity transmitter and receiver modules being realized in silicon photonics, which focus on single mode transmission systems and current proposals for optical backplanes, which focus on strongly multimodal waveguides. Thus far there was no technology demonstrated which can merge these two worlds. In this thesis we propose a completely novel idea to solve this problem, based on recent research in long distance communications. In that work, higher order modes travelling in a large core optical fiber are excited and detected using a complex silicon photonics integrated chip, as shown in the picture below.



The objective of this thesis is to evaluate if the approach shown in the picture above can also be used for short optical links over an optical back plane. In that case we can imagine a linear array of  silicon grating couplers exciting and detecting higher order modes in a rectangular polymer waveguide running over an optical backplane.

In this thesis you will first evaluate the feasibility of this idea, investigate the effects of mode mixing in the waveguide, propose and design suitable transmitter/receiver chips and optimize the waveguide shape. Finally we will setup a demonstrator for evaluating the idea. The work will be carried out in a collaboration between the Photonics Research Group and CMST.


photonics, optical interconnect, optical backplane 


Ardoyen CMST , technicum, at home.