where the first term on the right side denotes the dispersion-based phase modulation-intensity
modulation conversion; c represents the optical wave propagation velocity in free space; D refers to
the accumulated dispersion of the SMF link; 0 denotes the wavelength of the optical carrier; and fm
represents the modulating signal frequency. The lower and higher 10 dB cutoff frequencies are
4.7, 16.3 and 18.3 GHz, respectively, which optimally exploit the allowable bandwidth about 4.7 to
16.3 GHz. Based on the transfer function of (1), a simulation frequency response correlates well
with the experimental results.