Evolution of fiber access networks

Photonic Integrated Circuits for NGPON2 ONU Transceivers (Invited)

“…Sci. 2020, 10, x; doi: www.mdpi.com/journal/applsci management [70]. The development of PIC solutions for access networks has already been reported, e.g., with an InP monolithic transceiver PIC for NGPON2 applications [75], the proposed layout has the potential to be implemented as an OLT and with filter redesigning as an ONU.…”

“…For each end technology, a different ONU is typically required. Currently, it is very common to have combined interfaces that allow multiple technologies to be handled within the same device, the so-called "combo" solutions [70]. Figure 2 illustrates some of the main existing characteristics of the ITU-T related technologies.…”

“…Moreover, a number of more aggressive and disrupting operators are investing in deploying NGPON2, merging the traditional concepts of time-multiplexed single-channel per direction PON combined with wavelength division multiplexing (WDM) [71]. This approach allows for further developing network flexibility concepts and the smooth evolution of offered data rates [70], i.e., up to 40 or 80 Gbit/s aggregated rates. An example of a PON with coexisting technologies supported by the current ITU-T standard series [71] is depicted in Figure 3.…”

“…For NGPON2, the OLT transceiver should contain four transmitters (Tx) and four receivers (Rx) with an internal wavelength mux/demux optical module. In the ONU, a 10 Gbps transceiver with both tunable Tx and Rx is required [70]. By employing wavelength-selective branching devices in ODN, losses can be diminished, nevertheless at the cost of wavelength transparency waiving.…”

“…Photonic integration can provide advantageous solutions to PON by limiting the number of optical and electrical interconnections and thus overcoming some of the bulk packaging restrictions, such as bandwidth, power dissipation, and cost [65,74]. Nevertheless, complexities can arise with the use of this technology, namely fiber interfacing difficulties, number of electrical connections, and possible high-density of components per device, which demands a high power dissipation management [70]. The development of PIC solutions for access networks has already been reported, e.g., with an InP monolithic transceiver PIC for NGPON2 applications [75], the proposed layout has the potential to be implemented as an OLT and with filter redesigning as an ONU.…”