在基于OIDFT或时间透镜的光OFDM系统中利用相位预加重降低峰均比
摘要
Phase pre-emphasis is theoretically studied and introduced to reduce peak-to-average power ratio (PAPR) in optical orthogonal frequency division multiplexing (OFDM) systems. In intensity modulated (IM) systems, simulations show noticeable PAPR reductions: 4.14 dB (N = 16) and 15.48 dB (N = 512) in time lens-based OFDM, N is the number of subcarriers. An equation is developed to calculate phase values and is proved to be effective. Optical implementing methods are proposed and analyzed. In a time lens-based OFDM system, phase pre-emphasis reduces fiber nonlinearity and results in a 5.2-dB increase of launch power at the bit error rate (BER) of 10 -6 . Simulations also show similar PAPR reduction and fiber nonlinearity mitigation in optical inverse discrete Fourier transformer (OIDFT) based OFDM systems.