A TWDM-PON with Advanced Modulation Techniques and a Multi-Pump Raman Amplifier for Cost-Effective Migration to Future UDWDM-PONs

Abstract

Abstract-Dense wavelength-division multiplexing passive optical networks (DWDM-PONs) and ultra-dense wavelengthdivision multiplexing passive optical networks (UDWDM-PONs) are strong candidates to future next-generation passive optical network stage 3 (NGPON3) access networks in order to satisfy increasing bandwidth demand, but their deployment is still a great challenge for telecommunication operators. PON (WDM-PON). In order to fulfill this aim, with reference to downstream traffic enhancement, two main novelties are presented: (a) the use of a multi-pump Raman amplifier (MRA) to satisfy the future necessity of large gain bandwidth; (b) the introduction of advanced modulation techniques to increase spectral efficiency and the future number of user channels (a less than -wide channel bandwidth providing / bitrate has been demonstrated). A coherent system has been also proposed and its main impairments have been evaluated. The MRA has been accurately optimized to minimize power consumption without compromising performances. In the upstream direction, a semiconductor optical amplifier (SOA) has been considered. The performances of the proposed TWDM-PON have been predicted through numerical simulations based on a system-level commercial CAD software. Time and wavelength division multiplexed PON (TWDM-PON) has already been chosen by ITU-T as one of the best architectures in brownfield contexts to allow the reuse of the optical distribution network (ODN). Our proposal exploits the advantages of TWDM in order to reach a balance between coexistence with legacy systems and gradual and cost-effective migration towards pure wavelength division multiplexed Index Terms -optical access networks, FTTH, NGPON3, TWDM-PON, Raman amplifier, SOA.

Optical Amplifiers for Access and Passive Optical Networks: A Tutorial

“…Other types of fiber amplifiers can be used for PONs: A thulium-based amplifier downstream and a praseodymium-based amplifier upstream [108][109][110][111][112][113][114]. Raman amplifiers can be used for PONs; however, if we take into account the cost and hazardous optical power, it is not the best solution for downstream transmission [115][116][117][118][119]. SOAs can be used as one of the most suitable candidates for future next-generation long-reach PONs.…”

Proposal for an SDN-Like Innovative Metro-Access Optical Network Architecture

“…In this case the estimated amplifier gain should be approximately 41.5 dB (otherwise, if SOA-base implementation would be adopted lower gain would be sufficient). In order to achieve large broadband amplification, multipump Raman amplifiers (MRAs) can be used: the use of Raman amplifiers in metro and access segment has been recently proposed [32]; the usage of MRA has recently been proposed also for PONs [33]. MRAs could be used instead of an integrated solution since the optical amplifiers can be placed outside the ROADM, before the AWG.…”

“…Therefore there are 6 amplifiers in each ROADM. In [33] a MRA with three pumps' configuration has been proposed with a total electrical power of 405 mW for about a 25 dB optical gain over a 90 nm bandwidth. Extending this result, a value of ≅ 0.8 W can be estimated to get the required gain.…”

Raman amplification by employing data modulated pump signals for bi‐directional communication

“…In ref. , a multi‐pump configuration along with advanced modulation schemes is proposed to accommodate future gain bandwidth requirements of the WDM‐PONs. In ref.…”