Optimal duty cycle in RZ codified data for 10Gb/s optical access networks

We evaluate the duty cycle in RZ coded signals in an optical access network emulated with two users at a bit rate of 10 Gb/s. An optimum duty cycle of 75% was found for a fibre link of 25 km. This value remained when increasing the launched power up to 12 dBm. The range for 1 dB penalty was between 60% and 80%. In comparison with NRZ, with the optimum duty cycle the performance in terms of the receiver sensitivity for a BER of 2×10 −4 improved by almost 4.5 dB while the bandwidth between neighbour users was limited to 45 GHz.