Enhanced performance of RSOA-based WDM PON by using Manchester coding

Employing inverse return-to-zero and Manchester formats for uplink wavelength reuse in RoF systems

“…One branch of the dual-drive MZM is driven with NRZ format at specific data rate, while the other branch is loaded with alternative voltage of '1' and '0' at a double data rate as of the NRZ [14,15], so that in each NRZ bit slot there is always optical power within half bit duration. In this way the generated optical Manchester pulses featuring the same optical power in each bit slot as shown in Fig.…”

Recent progresses in RSOA-based WDM PON

“…Thus, it may be unavoidable to utilize a mitigation technique of the discrete reflections for the practical development of the RSOA-based WDM PON [10]. To mitigate the effects of the reflection, we have either increased the orthogonality between the upstream and downstream signals (by using the Manchester coding or sub-carrier multiplexing), or used the seed light with a broad optical spectrum (by using the ASE source as the seed light or dithering the downstream signal used as the seed light) [11]- [15].…”

Design Issues in RSOA-based WDM PON

“…This is based on the fact that the amplitude fluctuation slower the carrier response can be compressed in the saturation region. However, it requires the high injection power to the RSOA, and hence, it becomes less effective as the loss budget becomes high [5]. To solve this problem, we have proposed to use different modulation formats such as Manchester coding [5] and sub-carrier multiplexing (SCM) [12] instead of the conventional non-return-to-zero (NZR) format for the downstream signals.…”

“…However, it requires the high injection power to the RSOA, and hence, it becomes less effective as the loss budget becomes high [5]. To solve this problem, we have proposed to use different modulation formats such as Manchester coding [5] and sub-carrier multiplexing (SCM) [12] instead of the conventional non-return-to-zero (NZR) format for the downstream signals. In this case, since the remodulation noise exists outside the upstream signal's bandwidth, the remodulation noise does not affect the BER performance of the upstream signal.…”