In LTE, a new X2-interface is defined to facilitate direct communication between neighboring eNBs. Since LTE is an all-IP network, the X2-interface traffic currently needs to be routed and transponded in L3 at the edge router by IP addressing. As mobile data increases, it is a promising trend to backhaul mobile services based on PON. In this paper, an effective approach for eNB inter-communication over TWDM-PON is proposed. By associating the IP address of eNB and the MAC address of ONU, the “inter-eNB communication in L3" can be mapped into "inter-ONU communication in L2" and transponded via the protocol of PON at the OLT. Thus, fast and cost-effective eNB inter-communication can be realized based on TWDM-PON within one wavelength channel and between different wavelength channels. The increasing data traffic pressure to the core network can also be alleviated.
We present a novel upstream burst-mode equalization scheme based on optimized SOA cascade for 40 Gb/s TWDMPON. The power equalizer is placed at the OLT which consists of two SOAs, two circulators, an optical NOT gate, and a variable optical attenuator. The first SOA operates in the linear region which acts as a pre-amplifier to let the second SOA operate in the saturation region. The upstream burst signals are equalized through the second SOA via nonlinear amplification. From theoretical analysis, this scheme gives sufficient dynamic range suppression up to 16.7 dB without any dynamic control or signal degradation. In addition, a total power budget extension of 9.3 dB for loud packets and 26 dB for soft packets has been achieved to allow longer transmission distance and increased splitting ratio.
Detailed numerical investigation of self-seeded colorless ONU transmitter using quantum dot (QD) SOA as the intensity modulator for symmetric 40 Gb/s TWDM-PON has been developed. It is shown that the QD SOA-based intensity modulator is able to support 10 Gb/s OOK upstream signal transmission with an optical extinction ratio of over 10 dB. Chromatic dispersion compensation free of 20 km passive transmission has been achieved for error free reception. Moreover, the system performance and power budget have been analyzed and discussed for different transmission distance and split ratio.
Metro-access network is a newly emerged network which combines the traditional separated metro network and access network together into a converged system. It serves more users in a larger geographical area, meanwhile maintaining a simplified network hierarchy which inherits the low cost, large bandwidth, and high reliability of PON. In this paper, a novel remote node for metro-access converged network is proposed, which supports multi-type PON colorlessly, meanwhile maintains single specification for all subscribers. In addition, it saves nearly half of the spectrum resource in the metro part.