A new signal combination for 3-channel duty-cycle division multiplexing technique

Duty-cycle division multiplexing (DCDM) technique allows the transmission of multiple users transmission over single wavelength. In this technique return-to-zero (RZ) signals with different duty-cycles are used to electrically combine users signals. In this paper a new signal combination method for 3-channel DCDM is proposed. The modified system which uses dual drive Mach Zehnder Modulator (DD-MZM) is simulated and the DDMZM bias voltages and splitting ratio is optimized for proposed system. The performance of system is demonstrated as BER of users. Results show that the proposed system at BER of 10^-9 has 1 dB advantage over normal DCDM. Performance of system over 8 channels WDM network is also investigated. It is shown that the performance gap between proposed system and normal DCDM increases by decreasing the channel spacing.