A scheme to expand the delay-bandwidth product in the resonator-based delay lines by optical OFDM technique

We propose a novel scheme to expand the inherent limit in the product of the optical delay and the transmission bandwidth in resonator-based delay lines, with the optical orthogonal frequency division multiplexing (OOFDM) technique. The optical group delay properties of a single ring resonator were theoretically studied, and double-carrier OOFDM signals were transmitted through such a device in the experiment, where the subcarrier-frequencies matched those of the resonant modes in the device. The results show that, although the delay-bandwidth product (DBP) is limited in the order of 50 ps×10 Gb/s for signals on each of the sub-carriers, the total DBP of the system is doubled to 2×50 ps×10 Gb/s due to the double-carrier transmission.