All-Optical Multiwavelength Ring Networks

In this thesis, several issues related to all-optical multiwavelength ring networks, have been addressed and studied. Several types of crosstalk, occurring in optical networks, are described. And, an easy to apply method, Chernoff's Bound, is proposed to give a safe estimation of the error probabilities caused by crosstalk. The bound has been compared to other methods found in literature. Phased Array (PHASAR) based Optical Add/Drop Multiplexer (OADM) designs have been theoretically and experimentally investigated, with respect to the crosstalk generated by the OADM. It could be concluded that a double-PHASAR OADM has the best performance. The foldback OADM performs, in theory, only a little less good. However, from experiments it was found that the foldback OADM is very sensitive to reflections inside the PHASAR, which limit the performance of this OADM. The crosstalk caused by the switches in the OADM can be minimised by the use of 1 x 2 switch structures or dilated 2 x 2 switches, In these structures the near-end-crosstalk is eliminated. The behaviour of Erbium Doped Fibre Amplifiers (EDFAs) in optical multiwavelength networks has been investigated with several models. An electrical circuit simulator, SPICE, has been used to study the dynamic behaviour of EDFAs in ring networks. Off-line as well as on-line wavelength allocation methods for ring networks have been described. A new Quasi-on- line allocation algorithm has been proposed and studied using a ring network simulator. This new algorithm results in less fragmentation of resources (wavelengths). Finally a laboratory scale all-optical multiwavelength ring network is designed and implemented. With this ring network experiments have been performed, like performance measurements and ring lasing experiments. It could be concluded that ring network lasing results in a stabilised EDFA-gain.