Heterogeneous Optical Access Networks: Enabling Low-Latency 5G Services With a Silicon Photonic Smart Edge

Abstract

In the 5G era, optical fronthaul is a major challenge in meeting growing demand. Edge computation and coordinated multipoint for 5G have stringent requirements for high throughput and low latency, either in single-wavelength or wavelength-division-multiplexing fronthaul. We propose a new silicon photonic solution to deliver 5G services on existing optical access networks with colorless optical network units, such as passive optical networks. The newly added 5G services form a heterogeneous optical access network. Using the existing fiber infrastructure, broadband services coexist with new 5G signals that can densify 5G coverage. The proposed scheme is both wavelength-selective (in the distribution network) and colorless (at the end user site). We use silicon microring modulators to create subcarriers slaved from the broadband service distributed carrier; additional microring modulators generate 5G signals exploiting those subcarriers. We experimentally validated the successful coexistence of 5G signals (various formats) with a broadband signal (various formats).

Silicon Photonics in Optical Access Networks for 5G Communications

“…A real-time oscilloscope and offline processing emulated the ONU functions. We validated good performance of all signals as reported in [13], with the bit error rate (BER) measurements given in Fig. 4(b).…”

“…In [13] we presented experimental results where we intercept the downlink digital wideband signals at the smart edge and add 5G signals. The overlaid analog RoF combined with the digital signal is sent to the local distribution network.…”

“…Our proof-of-concept demonstrations used bare SiP chips with high coupling loss, requiring additional amplification [13], [14]. Commercial packaging would reduce this to a few dB, and the microrings in the bus introduce low filtering and propagation loss in their passband.…”

“…Commercial packaging would reduce this to a few dB, and the microrings in the bus introduce low filtering and propagation loss in their passband. Our SiP MRM bus offers good scalability for WDM; the short waveguide length makes incremental loss in adding channels small (loss is dominated by coupling even with efficient commercial packaging); please see [13], [15] for a fuller discussion.…”

High Performance Ge-on-Si Photodetector With Optimized Light Field Distribution by Dual-Injection

“…data center, communication, sensing, high-performance computing and artificial intelligence area [6,7]. As the key component of the receiver, silicon-based photodetector has significant influence on the performance of the entire transceiver system.…”