We examine a peak-to-average power ratio (PAPR) reduction effect in an optical fiber link using a fractional Fourier transform (FrFT). Fractional OFDM (FrOFDM) based on FrFT in place of discrete Fourier transform is a multiplexing approach that can balance the pros and cons of subcarriers in the time and frequency domains while keeping its orthogonal condition. A careful investigation of the PAPR behavior of a FrOFDM signal confirms that its PAPR can be minimized at a point where a Nyquist pulse train is formed by a time-lens effect. With emphasis on this low-PAPR characteristic of a Nyquist pulse train, the signal quality degradation owing to fiber nonlinearity can be mitigated. A 1.0-dB signal quality improvement after propagation in a dispersion-compensated fiber link is demonstrated in a simulation for a 12Ã10-Gbaudâs 16 QAM FrOFDM signal in comparison with that of a conventional OFDM.
Nagashima, T., Cincotti, G., Murakawa, T., Shimizu, S., Hasegawa, M., Hattori, K., et al. (2017). Peak-to-average power ratio reduction of transmission signal of all-optical orthogonal time/frequency domain multiplexing using fractional Fourier transform. OPTICS COMMUNICATIONS, 402, 123-127 [10.1016/j.optcom.2017.05.055].