Optical Power Measurement And Optical Receiver - Deviser S7200 User Manual

Part II: Settings and Measurements
6-14

Optical Power Measurement and Optical Receiver

6-14.1 Optical Connectors and Adapters
Fiber connectors are the most common passive device used in the field of fiber-optic communications.
These components connect the endfaces of two optical fibers, allowing the continuous transmission of
optical signal. In an optical communications system, connectors appear at nearly every juncture: fiber end-
faces, passive and active optical components' input and output ports, fiber jumpers, and more.
An optical fiber connector is composed of a pin and connector. For example, with the FC/PC connector
type, "FC" specifies one of several external connection types. (Other external connection formats include
SC, ST, LC, MU, MT-RJ, D4, and E2000.) "PC" indicates the shape of the pin (or "endface"), which can be of
the PC, APC, or UPC standards.
Let's take a closer look at these different types of fiber endface.
Straight physical contact (PC)
The fiber ends are pressed together in the connector. There is no air gap left to cause reflections. The return
loss is 30 – 55 dB. This is the most common connector type for single mode fibers (e.g. FC/PC, ST, SC/PC, DIN,
HMS, and E2000 connectors).
Slanted (angled) physical contact (APC)
In these connectors, the ends of the fibers are slanted. Again, no air gap is left. This gives the best return loss
(60-80 dB). These connectors are used for high-speed telecom and CATV links (e.g. FC/APC, SC/APC, and
E2000-HRL connectors).
Straight air gap
Inside these connectors is a small air gap between the two fiber ends. Their return loss is less than 14 dB and
the reflection is fairly high. Straight air gap connectors (e.g. ST connectors), are used for multimode fibers.
FC Connector
The S7200 uses the FC/SC/ST replaceable universal connector interface. Users may replace these with
different connector interfaces as needed for field applications.
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SC Connector ST F Connector