The two cores of the eight-core optical cable are used for communication

In an eight-core optical fiber cable, typically two cores are actively used for communication—one for transmitting data and one for receiving—while the remaining cores serve as spares or for redundancy.

Core Allocation in Multi-Core Cables

In fiber optic networks, each device generally requires two cores for duplex communication: one core to send data and another to receive it . In an eight-core cable, this means that a single device connection can use two cores, leaving the other six cores available for other purposes such as:

• Spare cores: Reserved for future expansion or additional devices .
• Redundant cores: Used to maintain network reliability in case of a core failure .
• Multiplexing or branching: Some cores may be allocated to connect multiple devices or split signals across different network paths .

Practical Applications

Eight-core cables are commonly used in scenarios where multiple devices or high-speed connections are required. For example:

• Data centers: Two cores may connect a 40G or 100G interface, while the remaining cores can be used for future upgrades or redundancy .
• Point-to-point links: Only two cores are needed for a single duplex link, but extra cores allow for network growth without replacing the cable .

Summary

Using two cores for active communication in an eight-core optical cable is standard practice. This approach ensures efficient data transmission while providing flexibility for redundancy, spare capacity, and future network expansion. The remaining cores enhance reliability and scalability, making multi-core cables a practical choice for modern optical networks .