A novel group of interleaved orthogonal frequency division multiplexing (IL-OFDM) and partial transmission IL-OFDM (PT-IL-OFDM) schemes are proposed for optical coherent detection. In the interleaved operation, the odd (or even) subcarriers of an OFDM symbol are reserved (closed). Such an interleaved arrangement can gain the tolerance toward phase noise induced interchannel interference (PN-ICI). Meanwhile, the peak to average power ratio (PAPR) of an OFDM signal can be significantly reduced. However, half of the capacity is sacrificed for the interleaved operation. By exploring the time domain symmetry property of IL-OFDM, the concept of PT-IL-OFDM is proposed to double the capacity of IL-OFDM. Consequently, PT-IL-OFDM can gain the merits of low PAPR and a high tolerance toward PN-ICI without capacity sacrifice. Numerical simulation verified the advanced properties of IL-OFDM and PT-IL-OFDM.