Encoding ASK labeled CSRZ-DPSK payload by using only one dual-drive Mach-Zehnder modulator with enhanced label performance

This theoretical study presents a novel modulation scheme which simultaneously encodes the amplitude shift keying label on the carrier-suppressed return-to-zero differential phase shift keying payload using only one dual-drive Mach-Zehnder modulator. Compared with the previous scheme, in which three optical modulators are required, we offer a simple, compact, and cost-effective method. We theoretically evaluate and simulate the performance differences between the two schemes. It is found that the sensitivity of the label is 2 dB better than the previous scheme and the payload, with optimized extinction ratio in the electroabsorption eraser, has almost the same performance after 120-km standard single-mode fiber transmission.