Transmitters for two-tier optical data-packet labelling in advanced IP networks

Semiconductor lasers send information over the Internet in packets. Evaluation of a new transmitter concept for optical data packet switching suited to optical networks that can switch channels rapidly is presented. In such networks optical paths are established that are switched using labels and a wavelength label, in addition to a frequency-modulated tone as a second label, that is encoded by optical frequency modulation, FM or FSK, is used. The new second label allows for fast re-assignment of the packet to an alternative transport means in the fibre if required. Both simulation and experiments have been performed to assess transmitter performance of the proposed combined-labelling scheme. To this end, a widely tunable laser is used to convert the colour (wavelength) and thereby efficiently route the optically labelled packets in a network. At the receiver end the data can be re-assembled using the colour as a guide, even if it were sent in bursts. Within the EU-STOLAS project, laser performance simulations have been done and fast measurements carried out at specific ITU-channel wavelengths.