Did you know that approximately 100 fiber optic connectors have been introduced in the worldwide market place, but only a few could survive? LC, SC, Biconic and Deutsch 1000 are the names of those successful connectors. According to The Fiber Optic Association, ‘Deutsch 1000’ was probably the first commercially successful fiber optic cable connector from the late 70s.
Evolution of the Connectors’ Design
When mentioning the word ‘Cable Connector’, an image of ‘male connectors with a ring or cap (typically a metal one)’ probably comes to mind. It is also known as ferrule design, which is quite useful because it easily and directly connects electronic devices such as a computer desktop, sound system and LEDs. Ceramic ferrule came into existence in the mid-80s, and it completely changed the connectors’ design. Those connectors were extensively used for telecom networks in the 1980s and early 1990s. The best part of ceramic ferrule was its hardness and precision. In this design, fibers could be accurately located for alignment and ferrules could be allowed to touch. Later on in the late 90s, ceramic ferrule got some tough competition from ‘small form factor (SFF) connectors’.
Some of the popular connectors over the years include:
- ST: Straight Tip is a trademark connector of AT&T. It is still very popular for multimode networks.
- SC: Subscriber Connector is an expensive snap-in connector. It was standardized in TIA-568-A. It is also available in a duplex configuration.
- FC: Ferrule connector was very popular in the late 80s and 90s. It is a single mode connector. It screws on firmly. Later on, it was replaced by SC’s and LC’s.
- LC: The Lucent Connector is a small form factor connector. It comes in half the size of the SC connectors. It was highly used for single mode connectivity.
- FDDI & ESCON: FDDI stands for ‘Fiber distributed data interface’ and ESCON stands for ‘Enterprise Systems Connection’. These connectors are generally used to connect to the equipment from a wall outlet, but the rest of the network will have ST or SC connectors.
- LX-5: This is like an LC, but with a shutter over the end of the fiber.
Every fiber connection has two values:
1) Attenuation or insertion loss and
2) Reflection or return loss.
Measurements of these parameters are now defined in the International Electrotechnical Commission (IEC) standard 61753-1. The standard gives five grades for insertion loss where A is considered the best, D the worst and M for multimode. The other parameter is return loss, with grades from 1 for the best to 5 for the worst.