In this paper, we investigate the impact of the transmitter finite extinction ratio and the receiver carrier recovery phase offset on the error performance of two optically preamplified hybrid M-ary pulse position modulation (PPM) systems with coherent detection. The first system, referred to as PB-mPPM, combines polarization division multiplexing (PDM) with binary phase-shift keying and M-ary PPM, and the other system, referred to as PQ-mPPM, combines PDM with quadrature phase-shift keying and M-ary PPM. We provide new expressions for the probability of bit error for PB-mPPM and PQ-mPPM under finite extinction ratios and phase offset. The extinction ratio study indicates that the coherent systems PB-mPPM and PQ-mPPM outperform the direct-detection ones. It also shows that at PB-mPPM has a slight advantage over PQ-mPPM. For example, for a symbol size and extinction ratio  dB, PB-mPPM requires 0.6 dB less SNR per bit than PQ-mPPM to achieve . This investigation demonstrates that PB-mPPM is less complex and less sensitive to the variations of the offset angle than PQ-mPPM. For instance, for ,  dB, and PB-mPPM requires 1.6 dB less than PQ-mPPM to achieve . However, PB-mPPM enhanced robustness to phase offset comes at the expense of a reduced bandwidth efficiency when compared to PQ-mPPM. For example, for its bandwidth efficiency is 60 % that of PQ-mPPM and for . For these reasons, PB-mPPM can be considered a reasonable design trade-off for M-ary PPM systems.