When we choose OTDR or power meter, we usually need to choose the right connector type.

Connector Types:

Normally speaking the connector type are :SC.LC.FC .ST.

SC connector was one of the first connectors to hit the market following the advent of ceramic ferrules. Sometimes referred to as the “square connector” SC connector uses a push-pull latching mechanism. It has a larger connector housing, and a larger 2.5mm ferrule. Take Shinho X-5002 laser source for example.

LC connector was less successful, partly because of the initially high license fees from inventor Lucent Corporation. The LC utilizes a latch as opposed to the SC locking tab. It has a smaller connector housing, and a smaller 1.25mm ferrule. it huge popularity in datacoms and other high-density patch applications.

The FC connector is a fiber-optic connector with a threaded body, which was designed for use in high-vibration environments. It is commonly used with both single-mode optical fiber and polarization-maintaining optical fiber. Following is connector on Shinho X-5001 power meter.

ST stands for Straight Tip - a quick Release bayonet style Connector developed by AT&T. ... ST Connectors are among the most commonly used Fiber optic connectors in networking applications. They are cylindrical with twist lock coupling, 2.5mm keyed ferrule.

What is UPC and APC?

There are four types of connector ferrule polishing style in all. UPC and APC are two types of them. UPC stands for Ultra Physical Contact , APC stands for Angle Polished Connector.The main difference between UPC and APC connector is the fiber end face. UPC connectors are polished with no angle, UPC connectors are not exactly flat, however; they have a slight curvature for better core alignment.but APC connectors feature a fiber end face that is polished at an 8-degree angle. With UPC connectors, any reflected light is reflected straight back towards the light source. However, the angled end face of the APC connector causes reflected light to reflect at an angle into the cladding versus straight back toward the source. This causes some differences in return loss. Therefore, UPC connector is usually required to have at least -50dB return loss or higher, while APC connector return loss should be -60dB or higher. In general, the higher the return loss the better the performance of the mating of two connectors. Besides the fiber end face, another more obvious difference is the color. Generally, UPC connectors are blue while APC connectors are green. The following figure picture shows the differences mentioned above intuitively.

In the current market, the APC connectors are widely used in applications such as FTTx, passive optical network (PON) and wavelength-division multiplexing (WDM) that are more sensitive to return loss. With those applications that call for high precision optical fiber signaling, APC should be the first consideration, but less sensitive digital systems will perform equally well using UPC.

Shinho has a full series of fiber testing instruments, with different connector available. Contact the sales to pick the suitable one for you.