Most modern SFP optical modules use LC connectors, while SC connectors are typically found in legacy or lower-density applications.

Connector Type in Optical Modules

LC (Lucent Connector) is the most common connector for modern SFP and SFP+ modules due to its small form factor, compact size (1.25mm ferrule), and high port density, making it ideal for data centers, servers, and cloud computing environments . LC connectors use a latch-locking mechanism and allow for higher density connections compared to SC connectors . SC (Subscriber Connector) connectors are larger (2.5mm ferrule) and feature a push-pull coupling mechanism. They are robust and reliable but occupy more space, which limits port density. SC connectors are still used in legacy networks, enterprise systems, and long-distance telecom applications, where durability is prioritized over compactness .

Key Differences Between LC and SC

• Size: LC is half the size of SC, allowing twice the port density .
• Mechanism: LC uses a latch-lock, SC uses push-pull .
• Applications: LC dominates in modern SFP modules and high-density data centers, SC is common in older networks and lower-density setups .
• Ferrule Diameter: LC = 1.25mm, SC = 2.5mm .

Practical Implications

If you are working with current SFP or SFP+ modules, the optical module is almost certainly LC. SC connectors may still appear in older equipment or in scenarios where robustness and ease of handling are more important than space efficiency . Adapters or hybrid cables (SC-LC) can bridge connections between different connector types if needed . In summary, LC is the default choice for modern optical modules, while SC is primarily used in legacy or less space-constrained environments.