2021 Volume 25 Issue 3 Pages 103-109
During the transition from current passive optical networks to next-generation systems, the error rate is expected to increase owing to the coexistence of on-off keying (OOK) which is used in the current optical network and phase-shift keying (PSK) for the next-generation system. Moreover, the currently used bias transmission method is problematic owing to excessive transmission power. Therefore, in this study, a trellis coded modulation, which is an error correction method, is proposed and evaluated, and a clip transmission method, which is a power reduction method, is applied to an environment where OOK and 8-PSK coexist. The effectiveness of the proposed approach was confirmed through a reduction in the received power of approximately 2.9 and 4.5 dB in PSK and OOK, respectively.