MSc graduation project PAM4 Duobinary


The need for higher speeds in the telecommunication networks have always been around. For access networks, specifically PONs, the increase in data rates has historically been provided in a linear fashion. By designing and using higher bandwidth optics and electronics the data rates increased. In recent years this has come to a halt at 10 Gbps. FSAN, one of the standardization agencies for access networks, has released the NGPON2 standard last year. Instead of increasing the data rate per wavelength, they opt to increase the data rate by utilizing multiple wavelengths and tunable transceivers in the ONUs.

IEEE, the other standardization agency for access networks, is still debating whether to go towards multiple wavelengths or stay at a single wavelength. In the latter case they will opt to increase the data rate by using more sophisticated modulation formats instead of NRZ OOK. Strong contenders are duobinary modulation and 4 level Pulse Amplitude Modulation (PAM). Both modulation formats allow to double the data rate in the same bandwidth. In this assignment you will be looking deeper into both modulations formats.

The assignment will consist of two parts:

Theoretical Assignment

You will need to do an in depth analytical investigation of the characteristics for both modulation formats, specifically for use in access networks. You will provide an analysis of both modulation formats and their incurred penalties in terms of e.g. bandwidth, dispersion, noise, chirp, jitter, filtering etc.

Experimental Assignment

You will need to design a realtime lab setup to verify the use of PAM4 and/or duobinary in access networks. To show the feasibility only commercially available GPON transceivers will be used. You will need to convert binary signals to PAM4/duobinary signals, transmit them over an optical link, and decode them back to binary. Some practical soldering skills might be an advantage.

For more information, please contact Dr. Eduward Tangdiongga ( flux 9.099) or flux 9.091)