Scalable and reconfigurable generation of flat optical comb for WDM-based next-generation broadband optical, access networks

A tunable comb generator (TCG) by cascading a single phase modulator (PM) with two identical intensity modulators (IMs) is proposed for the scalable and reconfigurable generation of fiat optical comb. Detailed theoretical analysis is performed to find out the optimized condition for flat optical comb generation using the proposed TCG and the scalability of the generated optical comb is also analyzed under the optithized condition. An experiment is conducted to verify the feasibility of the TCG and the experimental results agree well with the theoretical prediction. The reconfigurability and stability of the obtained optical comb are discussed as well in the experiment. After that, the obtained optical comb is utilized as the optical source for a wavelength-division multiplexed radio-over-fiber (WDM-RoF) system and a hybrid WDM orthogonal frequency-division multiple access passive optical network (WDM-OFDMA-PON). Two corresponding experimental demonstrations are presented to verify the feasibility of employing the obtained flat optical comb as the WDM optical source, respectively. In the WDM-RoF system, 17 WDM channels each carrying 16 x 5 Gb/s non-return-to-zero (NRZ) data have been up-converted to 10 GHz simultaneously. In the hybrid WDM-OFDMA-PON, 17-channel OFDM-WDM double-sideband (DSB) signal achieving 10.85 Gb/s traffic per channel is successfully transmitted for both wired baseband OFDM access and wireless 10 GHz OFDM access. (C) 2014 Elsevier B.V. All rights reserved.