In fiber optic communications, there is a trend towards flexible and transparent networking, meaning that the signal should remain in the optical domain as much as possible, to reduce energy consumption and avoid electronic bandwidth limitations. At the same time there is a trend towards coherent systems with heavy electronic digital signal processing in the receivers. Optical performance monitoring (OPM) deals with techniques to meet transparent networks by optically measuring and estimating properties like signal-to-noise ratio and signal distortions. To do this for coherent data meets several challenges, since the data is often heavily distorted before being detected and electronically equalized. On the other hand, channel estimation (CE) is somewhat easier for coherent signals, as it can be obtained from the equalizer electronics. In this project we plan to develop new techniques for OPM and CE in coherent networks. In particular we aim to study two approaches: (i) pilot-tones, which will facilitate OPM by yet being possible to suppress in the coherent receiver electronics, and (ii) training sequences, which will simplify the coherent reception by relaxing demands on laser line widths, while also facilitating CE. The project will cover both fundamental theory and conceptual developments, although the main focus will be put on experimental demonstrations. It aims to cover one PhD student including supervision during the 5 years of the PhD project.
Professor at Microtechnology and Nanoscience, Photonics
Funding years 2012–2015