1 Postdoctoral position in Conception of a communication chain on optical fiber based on filterbank modulations in Belgium | Université Libre de Bruxelles

We are seeking a highly motivated post-doctoral researcher to join our research program in the area of coherent communications on optical fiber. The researcher will be involved in the design of a filterbank communication chain and in its simulation on a new experimental setup acquired by the OPERA department at ULB.

Candidates must have a Ph.D. in Electrical Engineering, Physics Engineering, or other closely related areas. Experience in signal processing for digital communication or optical fiber instrumentation is desired. The candidate should be in an international mobility situation.

The candidate should have demonstrated the ability to perform theoretical analysis and experimental work, publish papers, and to work independently and in an interdisciplinary team.

In wavelength-division multiplexing (WDM) optical fiber communications systems, increasing the spectral efficiency is a key target in order to respond to the new capacity requirements. This can be achieved on each optical channel by using high-order modulation formats coupled with coherent detection and signal processing algorithms at the receiver to compensate digitally for the channel impairments. When multiple optical channels are considered together, the spectral efficiency is also strongly reduced by the frequency gaps introduced between the optical channels to prevent mutual interference.

We have recently proposed to make use of the filterbank modulations in order to achieve the best spectral efficiency/complexity trade-off. Filterbank modulations enable the orthogonal transmission of optical channels exactly spaced by the theoretical minimum equal to the channel aggregate symbol rate. Compared to state-of-the-art alternatives, filterbank modulations impose lower constraints on the design of the shaping pulses and are therefore more robust to implementation imperfections. They do not rely on the addition of any redundant information at the transmitter and deliver the highest possible spectral efficiency.

The goal of the project is to design the filterbank communication chain that realizes the best spectral efficiency/complexity trade-off and to implement it on a new experimental setup that reproduces the optical fiber communication channel. The setup supports the digital modulation of two time/frequency synchronized optical carriers at the transmitter and the coherent demodulation followed by digital signal processing at the receiver. It is necessary to derive analytical models of the optical fiber channel (including the transceiver) based on which the compensation algorithms can be conceived and to validate the communication chain on hardware.