Experimental demonstration and analysis of all-optical label swapping based on RZ-DQPSK/IRZ-ASK modulation format

A novel optical return zero differential quadrature phase shifted keying/inverse return zero amplitude shifted keying (RZ-DQPSK/IRZ-ASK) orthogonal modulation format scheme for all-optical label swapping is analyzed theoretically and experimentally. The transmission characteristics of RZ-DQPSK/IRZ-ASK modulation format transmission system are demonstrated. Results show that high extinction ratio is obtained for IRZ-ASK label signal while at the same time the all-optical label swapping, differential quadrature phase shifted keying (DQPSK) payload signal is hardly affected. It requires only 0.9 dB higher power penalty compared to 21.4 Gbit/s RZ-DQPSK modulation format and less than 2 dB transmission penalty after 60 km. The proposed scheme is a practical solution for meeting the data rate and cost-efficiency of the optical links simultaneously in future all-optical label swapping.