SC and LC Fiber Connectors You Should Know About in Fiber Patch Cables

Currently, SC and LC fiber connectors stand out among many connection options, becoming the most sought-after choices in the market. These two connectors are not only robust and durable but also deliver excellent performance, while being reasonably priced. However, a significant point to note is that due to differences in design and size, they are not interchangeable, which users need to consider when making their selection.

So, faced with such a dilemma, do you know which connector would best suit your project needs? And looking at future development trends, which one holds more potential and prospects? To help you make a better decision, we intend to delve into the core differences between SC and LC fiber connectors. Through detailed comparison and analysis, we will reveal their unique advantages and application scenarios.

SC Fiber Connector

SC, short for "Standard Connector," is also known as a square connector or snap-in connector. It is one of the industry's recognized standard connectors. Originating from the design ingenuity of JP Nippon Telegraph and Telephone, the SC connector was one of the pioneers to seize market opportunities following the advent of ceramic ferrule technology. Featuring a unique snap-in coupling mechanism, a square exterior, and a spring-loaded 2.5mm ferrule, the SC connector has been leading the industry since it became the first standardized connector under the TIA-568 telecommunications standard in 1991.

Although the SC connector initially faced market challenges due to its high price (approximately twice that of the ST connector), its widespread adoption eventually led to reduced production costs. With its excellent performance and efficient deployment capabilities, the SC connector held the title of the best connector until the introduction of the LC connector. Today, SC connectors are widely used in various fields of data communication and telecommunications, including single-mode fiber optic cables, analog CATV systems, GPON, GBIC, EPON ONU, fiber media converters, and point-to-point communication, as well as PON.

Furthermore, SC connectors strictly adhere to the FOCIS 3 fiber optic connector intermateability standard TIA-604-3, excelling in both simplex and duplex applications. They are also a premium choice for polarization-maintaining applications, showcasing their robust capabilities and broad applicability in the fiber optic connection domain.

LC Fiber Connector

LC, short for Lucent Connector, is named after its designer, Lucent Technologies. It was developed in response to the market's demand for smaller, lower-loss connectors. The LC connector innovatively uses a 1.25mm ferrule, making it half the size of the SC connector and earning it the nickname "small form factor connector."

With its compact size, simplified and accelerated operation, excellent insertion loss control, overall system reliability, and unique latch push-pull design, the LC connector quickly gained prominence in single-mode and multimode fiber deployments, gradually establishing its dominance. Despite initially facing limited attention due to the high licensing fees set by Lucent Technologies, the LC connector ultimately achieved widespread market acceptance due to its superior performance.

Today, the LC connector stands out in the fiber optic connector field, widely used in various high-density network environments, including but not limited to data communication, SFP and SFP+ transceivers, and XFP transceivers. Additionally, the FOCIS 10 fiber optic connector intermateability standard TIA-604-10 further classifies LC connectors into single-mode LC APC, single-mode LC UPC, and multimode LC UPC, catering to specific needs in different scenarios.

Overview of the Comparison Between SC and LC

Although LC and SC connectors exhibit similar excellent performance in terms of insertion loss and return loss, their primary differences lie in size and design. Specifically, the LC connector stands out due to its significantly smaller size, being only half the size of the SC connector. This compactness is the most notable advantage of the LC connector.

Name	Insertion and removal cycles	Ferrule diameter	Standard	Cost	Release year	Easy to use	Application Features
SC	1000	2.5 mm	TIA-604-3 (FOCIS-3)	Cheaper	1992	More relaxed	Data communication and telecommunications applications, such as GBIC, PON, etc.
LC	500	1.25 mm	TIA-604-10 (FOCIS-10)	Higher	2002	Not so easy	High packaging density, such as SFP+/SFP28, QSFP+ or QSFP28, etc.

Ferrule Size

The SC connector uses a standard 2.5mm ceramic ferrule, setting a benchmark in the industry. To compete with the SC connector, the LC connector was developed, featuring an innovative 1.25mm ceramic ferrule. This design is half the size of the SC connector's, highlighting the LC connector's more compact and efficient characteristics.

Design

The LC connector uniquely adopts a push-pull locking mechanism, which enhances both operational convenience and connection stability. In contrast, the SC connector retains a traditional latch-in coupling design for achieving close-fitting fiber optic connections.

Cost

Generally, SC connectors are more affordable compared to LC connectors. However, with economies of scale, the cost difference between the two tends to gradually narrow over time.

Applications

SC connectors are particularly suited for applications demanding high signal precision and sensitivity to return loss standards. However, due to their relatively larger size, SC connectors may be constrained in high-density deployment environments, limiting space optimization.

In contrast, LC connectors, with their compact size, are widely favored in settings like data centers and telecommunications exchange centers that prioritize high-density deployment. They effectively utilize limited space resources, meeting the demand for high integration and minimal spatial footprint in fiber optic connections.

Ease of use

Despite the size advantage that makes LC connectors popular in high-density environments, it also presents some operational challenges. Compared to SC connectors, the smaller size of LC connectors may make insertion and removal slightly more difficult.

Repeatability

The table above shows that SC connectors have 1000 mating cycles, which is twice that of LC connectors.

History and reputation

Since its inception in 1991, the SC connector has weathered three decades of challenges, maintaining a strong market presence due to its stable performance and widespread applications. In contrast, the LC connector, a newer entrant introduced in 2002, lacks the deep historical roots of the SC connector. However, with its compact size and excellent performance, the LC connector is rapidly catching up, demonstrating unprecedented market potential and competitiveness.

Use an adapter or cable to connect SC to LC

Converting between SC and LC connectors is quite straightforward; you just need to use an SC-LC or LC-SC adapter/cable. This interoperability ensures users have greater flexibility and convenience when building or adjusting fiber optic networks. Additionally, to enhance fiber connection efficiency and density further, users can opt for module boxes to centrally manage multiple LC or SC links using MPO cables.

Conclusion

poised to excel in future competition. Their compact design makes LC connectors an ideal choice for high-speed, high-density applications like advanced QSFP+, QSFP28, and 40GbE or 100GbE networks. However, it's worth noting that despite challenges in obtaining GBIC components, SC connectors maintain a solid position as an industry standard.

In terms of standardization, the importance of SFP+ and QSFP+ is undeniable, yet SC connectors are expected to continue playing a significant role in the coming years. For instance, SC connectors are favored in specific applications such as patch panels for their ability to easily swap cables in duplex sleeves. Therefore, while LC connectors show strong momentum, SC connectors are likely to retain their market competitiveness for a period of time.