New Technique for Suppression Four-Wave Mixing Effects in SAC-OCDMA Networks

A new technique invented for suppressing the FWM in SAC-OCDMA systems based on adding idle code at the sideband of the code construction to generate the virtual FWM power at the sideband of the signal, and then by subtracting these virtual FWM power from the original FWM power in the system and filtering the data part at the channel. This technique is applied for both SAC codes, Random Diagonal Code (RD) and Multi Diagonal Code (MD). Moreover, in terms of cost, the reported technique is considered a cost-effective as the LED light source is used to generate the sideband codes. The results showed that the FWM reduced approximately 25 dBm after using the technique. For example, in the RD code the FWM power at 40km fiber length and input power is 15 dBm using the SMF fiber type is approximately -55 dBm before using the technique, after using the technique at the same values of parameters the FWM power is approximately -90dBm. In other words, at the MD code the FWM power before using the technique is approximately -61 dBm, the same parameters values, however after using our technique the value of the FWM power is approximately -81dBm. However, These results gave impact on the Bit Error Rate (BER) also, for example the value of BER in the RD code at the input power -10dBm and 35km fiber length before using the technique is 1.6×10-23 and after using the technique the value of BER will become 4.05×10-28. In addition at the MD code the BER value before using the technique is 9.4×10-22 and after using the technique the value of BER is 7.4×10-31. Keywords—Optical code division multiple access (OCDMA); Spectral amplitude coding (SAC); Multi diagonal (MD); Random Diagonal (RD); Four-Wave Mixing (FWM); Light Emitting Diode (LED).)