Statistical UDWDM-PONs Operating With ONU Lasers Under Limited Tunability

Abstract

Abstract-We explore a new wavelength management for ultra-dense WDM-PONs with randomly distributed ONU wavelengths, controlled with limited thermal tunability. Static and dynamic wavelength assignment paradigms and heuristic assignment schemes for spectrum management are proposed, simulated and compared. ONU acceptances in activation processes and ONU availability ratios up to 99.99% are obtained in standard environmental conditions.

UDWDM-PON Using Low-Cost Coherent Transceivers With Limited Tunability and Heuristic DWA

“…The TLs are non-preselected with nominal wavelengths uniformly distributed in each band, and of lowcost DFB type with limited tunability adjusted by heating. DFB-lasers exhibit typically a constant linear variation with temperature of 0.1 nm/ºC approximately between 20 to 50ºC [19], covering 3 nm, thus enabling to tune up to 60 channels spaced at 6.25 GHz in C-band. This temperature range is easily reached with a Peltier, and also even just by heating applying an offset.…”

“…5). The OLT will control that all wavelengths are correct in power and allocation, during activation processes and in operation; making decisions about reassignments, if needed, to deal with temperature conditions, by heuristic DWAs schemes [19] and employing OLT-ONU messages in the Medium Access Control (MAC) layer.…”

“…Three heuristic channel assignment algorithms have been proposed to avoid collisions and efficiently organize the spectrum, suited for the SUDWDM-PON scenario with limited tunability [19]:…”

“…2). When the ONU lasers sources exhibit random wavelengths distributed in a band with limited thermal tunability, which is used to allocate wavelengths avoiding collisions, we have the Statistical UDWDM (SUDWDM) approach; hence, to efficiently distribute the spectrum in activation and also during operation, some Dynamic Wavelength Assignments (DWAs) algorithms schemes were introduced [19]. In this work we present the design of the COCONUT UDWDM-PON, by furnishing a WTTU approach and also introducing the proposed architectures for the ONUs at users' premises and for the OLT at the Central Office (CO), where to cope with the required full optical band, we characterize the WMs employed in the OLT realization.…”

1.25–3.125 Gb/s per user PON with RSOA as phase modulator for statistical wavelength ONU

“…10). Compared to 2 Â 2 heterodyne detection or single-PD coherent detection, 3 Â 3 intradyne detection has the theoretical 3-dB advantage of the sensitivity [12,[30][31][32][33]. The RSOA is maintained at the same conditions compared with 2 Â 2 heterodyne detection (P LO ¼3 dB m).…”