Data Center Fiber Optics

Understanding fiber optic connectivity is crucial for high-speed data center networking. This lesson covers common connector types and speed standards like QSFP28.

Common Fiber Optic Connector Types

• LC (Lucent Connector): The standard for modern enterprise networking. It features a 1.25 mm ferrule, uses a latching mechanism, and is compact, making it ideal for high-density environments using SFP/SFP+/SFP28 transceivers.
• SC (Subscriber Connector): Features a 2.5 mm ferrule with a push-pull mechanism. While once common in telecom, GPON, and older infrastructure, it is generally too bulky for high-density modern equipment.
• MPO/MTP (Multi-fiber Push-On): A multi-fiber connector designed for high-density applications. It can terminate 8, 12, 16, or more fibers in a single rectangular interface, commonly used for parallel optics in 40G, 100G, and 400G environments.

Speeds and QSFP28

QSFP28 (Quad Small Form-factor Pluggable 28) is a transceiver standard designed for 100 Gbps networking. It achieves this by aggregating four electrical lanes, each running at 25 Gbps.

• For 10G/25G: Use LC connectors (standard for SFP+/SFP28).
• For 100G Short Range (SR4): Use MPO connectors. These use parallel optics, requiring an 8-strand or 12-strand MPO/MTP cable to transmit across the four 25G lanes.
• For 100G Long Range (LR4/CWDM4): Use LC connectors. These utilize Wavelength Division Multiplexing (WDM) to send 100G data over just two fibers.