Optical modules and optical fibers between BBU and PTN

Optical modules and fibers form the backbone for high-speed, reliable connections between BBUs and PTNs or RRUs, supporting CPRI/eCPRI and PTN services with scalable bandwidth.Optical Modules1. 10G and 25G SFP Modules:In 2G/3G/4G networks, 10Gbps SFP+ modules are typically sufficient for CPRI interfaces, while 5G networks often require 25Gbps SFP28 modules to support eCPRI and higher bandwidth demands .Example: 10G SFP+ CPRI SR modules use 850nm VCSEL lasers and PIN photodetectors, supporting multimode fiber transmission up to 300m (OM3). 25G SFP28 modules support 70–100m on OM3/OM4 fibers . 2. GPON SFP Modules:GPON SFP modules integrate point-to-multipoint (P2MP) technology, allowing a single fiber to serve multiple endpoints, which can save fiber resources between BBU and RRU .GPON SFP OLT modules are installed at the central office, while ONU modules are deployed at the RRU or subscriber end, supporting bidirectional transmission over a single fiber with downstream 2.5 Gbps and upstream 1.25 Gbps . 3. WDM-Based Modules:CWDM and DWDM optical modules allow multiple wavelengths over a single fiber, enabling fiber resource optimization and supporting multiple RRUs from a single BBU pool .These modules are essential in fiber-scarce areas or for long-distance C-RAN deployments, supporting distances up to 40 km or more with proper power budgeting .Optical Fiber Deployment1. Direct Fiber Connections:Traditional BBU-to-RRU connections use point-to-point multimode or single-mode fibers, often with 3–6 fibers per BBU-RRU pair .Hybrid fiber cables can combine power and fiber in a single run, reducing tower congestion and simplifying installation . 2. Fiber-Saving Techniques:Using GPON SFP modules or WDM multiplexing reduces the number of fibers required, allowing multiple RRUs to share a single fiber or wavelength, which is cost-effective and scalable . 3. Hybrid and Expansion Equipment:Active optical fiber expansion devices support CWDM/DWDM, wavelength conversion, and flexible service access (Ethernet, PTN, PON, SDH, CPRI), enabling transparent upgrades without replacing existing BBU, RRU, or PTN equipment .These devices can expand a single fiber's capacity by up to 12 times while maintaining low insertion loss (