Differences Between Different Fiber Optical Connector I


Given the variety of splice options available to fiber network planners today, identifying the best fiber optical connector for FTTH can be overwhelming. Consequently, not much thought is given to connector selection with choice driven by cost, availability or what’s been used before. However, each fiber optical connector has its own unique design and therefore, pros and cons. Over time or depending on the project size, this can have a dramatic impact on deployment speeds and costs.

So what are the differences and what do they mean to your implementation? This table of common fiber optical connectors gives an overview of strengths and weaknesses.

1. SC Connector

The SC was developed by the laboratories at Nippon Telegraph and Telephone (NTT) in the mid-eighties, and was one of the first connectors to hit the market following the advent of ceramic ferrules. Sometimes referred to as the ‘square connector’, the SC has a push-pull coupling end face with a spring loaded ceramic ferrule. Initially intended for Gigabit Ethernet networking, it was standardized into the telecommunications specification TIA-568-A in 1991 and slowly grew in popularity as manufacturing costs came down. Due to its excellent performance, it dominated fiber optics for over a decade with only the ST rivaling it. Thirty years on, it remains the second most common fiber optical connector for polarization maintaining applications. The SC is ideally suited for datacoms and telecoms applications, including point to point and passive optical networking.

2. LC Connector

Considered by some to be the modern replacement of the SC connector, its introduction was less successful, in part due to initially high license fees from its inventor. Also a push-pull connector, the LC utilizes a latch as opposed to the SC locking tab, and with a smaller ferrule it is known as a small form factor connector. Having half the footprint of the SC connector gives it huge popularity in datacoms and other high-density patch applications, as its combination of small size and latch feature, making it ideal for densely populated racks/panels. With the introduction of LC compatible transceivers and active networking components, its steady growth in the FTTH arena is likely to continue.

3. FC Connector

The FC was the first fiber optical connector to use a ceramic ferrule, but unlike the plastic bodied SC and LC, it utilizes a round screw-type fitment made from nickel-plated or stainless steel. The connector end face relies on an alignment key for correct insertion and is then tightened into the adapter/jack using a threaded collet. Despite the additional complexity both in manufacturing and installation, it’s still the connector of choice for precise measuring equipment.

Initially intended for datacoms and telecoms applications, its use has reduced since the introduction of the SC and LC. These deliver similar performance to the FC but both have less expensive components and are quicker to connect. However, the screw-on collet of the FC does make it particularly effective in high vibration environments, ensuring that the spring-loaded ferrule is firmly mated.