Integrated optical frequency comb for 5G NR Xhauls.

Area of Science:

• Photonics and Optical Communications
• Wireless Networking and Mobile Communications
• Integrated Optics and Photonics

Background:

• Fifth-generation (5G) mobile networks require high-capacity, low-latency fronthaul and midhaul solutions.
• Traditional optical distribution networks face challenges in flexibility and scalability for 5G deployments.
• Photonic integrated circuits (PICs) offer a promising platform for compact and efficient optical signal generation.

Purpose of the Study:

• To demonstrate a flexible optical distribution network for 5G Xhauls using a photonic integrated circuit (PIC) based optical frequency comb (OFC).
• To evaluate the performance of an Indium Phosphide (InP) monolithically integrated OFC in a centralized radio access network (C-RAN) architecture.
• To assess the system's capability in simultaneously supporting fiber-optic and free-space optics (FSO) links for 5G fronthaul and midhaul.

Main Methods:

• Generation of a broadly tunable OFC using cascaded optical modulators on an InP PIC.
• Optical generation of two low-phase noise millimeter-wave (mmWave) signals.
• Integration of 12.5-km single-mode fiber (SMF) fronthaul and midhaul links with a 10-m FSO fronthaul link.
• Deployment of two 10-m reach 5G wireless access networks operating in the 26 GHz band (FR2).

Main Results:

• The integrated OFC-based system successfully supported simultaneous SMF and FSO links for 5G Xhauls.
• The system achieved performance compliant with 3rd Generation Partnership Project (3GPP) Release 15 requirements.
• A total wireless throughput of 900 Mbit/s was demonstrated for the 5G wireless access networks.

Conclusions:

• PIC-based OFCs provide a flexible and high-performance solution for 5G optical distribution networks.
• The demonstrated C-RAN architecture effectively integrates fiber-optic and FSO links for 5G fronthaul and midhaul.
• This approach paves the way for scalable and cost-effective 5G network deployments.