Performance study of a DWDM link with real-time characteristics

The Dense Wavelength Division Multiplexing is an optical technology which allows transmitting across a fiber many wavelengths, which can be added and dropped by means of passive optical components. A plugin link module, capable of building full duplex nodes in the Gb/s domain for systems with real-time requirements, is presented in this paper. To debug and characterize the link, the module is plugged into an host board developed for the NEMO experiment, a submarine neutrino telescope which has successfully applied the described technology. A specific application has been designed with the aim of measuring the performance of the module: an embedded processor on the FPGA initializes the link, starts BER test routines and monitors transceiver functionalities through the I2C bus. The communication with the processor is implemented by a simple RS232 asynchronous port. The performance in terms of BER and Jitter in dependance of power at the receiver is shown.