Analog Radio-over-Fiber Fronthaul by a WDM-PON employing Double RSOA Self-Seeding and Carrier-Reuse Techniques

Abstract

WDM-PON has been considered a promising solution for future fronthaul links concerning new mobile networks applications. However, in order to avoid inventory problems and reduce operation costs, there is a need for colorless sources, where the same basic optical source can be used regardless of the desired wavelength. Also, the digital RoF scheme, which has been employed so far, might require a bandwidth that is prohibitive even for optical fiber links. In this paper, we propose and numerically investigate a bidirectional colorless WDM-PON fronthaul transporting analog RoF signals as an alternative to meet these demands. All simulations were performed using a framework calibrated with experimental data. For the downstream, we employ a double-cavity self-seeding technique, while the upstream is performed by a cascaded-RSOAs carrier-reuse approach. BER and EVM simulation analysis are presented for various data rates, modulations formats and RF bands ranging from 1 to 5 GHz, demonstrating the feasibility of our proposed topology as a novel fronthaul approach.

Optimization of arrayed waveguide grating‐filtering response for efficient analog radio‐over‐fiber fronthaul over a wavelength‐division multiplexing passive optical network

“…The second part of our analysis concerns the EVM results for the transmission of RF signals under different AWG‐filters. In our earlier work, 13 the proposed fronthaul topology was investigated using a fourth order Bessel filter. Although the EVM results were satisfactory, a phase‐offset (ie, a constellation rotation) of about 10° was observed for all modulation formats and further investigation was deemed necessary.…”

“…More recently, we have started to investigate an improved WDM‐PON configuration as a 5G mobile fronthaul 12,13 . Given the stringent performance requirements of 5G, we have sought to assure higher quality SS carrier generation, as well as improved carrier erasure efficiency, by placing two RSOAs are each end of each of the fronthaul links 12 .…”

“…In order to further enhance the transmission performance, we recently proposed an improved WDM‐PON topology, 12 using a double‐cavity SS configuration at the OLT transmitter and a cascaded RSOA pair at the ONT receiver, to increase carrier‐erasure efficiency 12 . Also, in line to the driving applications for future PONs, we recently investigated the application of our latest topology as an analog fronthaul option to future RAN 13 …”

“…The optical links serving as the fronthaul architecture are part of the WDM‐PON network described above, which employs a double‐cavity SS transmitter for downlink and a cascaded‐RSOAs carrier‐reuse transceiver for the uplink. The details of the architecture are described in References 12,13. For the sake of completeness, the essentials are given as follows below.…”

“…In a previous work, we have proposed a wavelength‐division multiplexing passive optical network (WDM‐PON) topology, 12 which has also been investigated as a fronthaul architecture 13 . This is because, although TDM based standards are the most usual in commercial PON systems, 5G fronthaul applications are suited for WDM‐PON, since WDM‐PON can offer multiple, dedicated, point‐to‐point high bandwidth channels, free of time‐synchronization constrains 14 …”