All-Optical Multi-Channel Aggregator for QPSK to 16QAM Based on Time-Lens and Phase Reloader in Elastic Optical Networks

An all-optical aggregator consisting of time-lens and a phase reloader for two four-channel multiplexed quadrature phase shift keying (QPSK) signals to a wavelength division multiplexed (WDM) 16-ary quadrature amplitude modulation (16QAM) signal is proposed. The feasibility of the scheme is confirmed by the waveforms of the intermediate process and the constellations of input-output signals. The performance of bit error rate (BER) and error vector magnitude (EVM) values under different optical signal-to-noise ratios (OSNR) are analyzed to evaluate the system, and the OSNR penalties of the aggregated signal at the forward error correction (FEC) threshold are between 2.25 dB and 2.45 dB. This scheme potentially enables reconfigurable service and improves compatibility in elastic optical networks (EON).