Products
An optical fiber connector terminates the end of an optical
fiber, and enables quicker connection and disconnection than splicing. The
connectors mechanically couple and align the cores of fibers so light can pass.
Better connectors lose very little light due to reflection or misalignment of
the fibers. In all, about 100 fiber optic connectors have been introduced to
the market.
Application
Optical fiber connectors are used to join optical fibers
where a connect/disconnect capability is required. The basic connector unit is
a connector assembly. A connector assembly consists of an adapter and two
connector plugs. Due to the polishing and tuning procedures that may be
incorporated into optical connector manufacturing, connectors are generally
assembled onto optical fiber in a supplier’s manufacturing facility. However,
the assembly and polishing operations involved can be performed in the field,
for example, to make cross-connect jumpers to size.
Optical fiber connectors are used in telephone company
central offices, at installations on customer premises, and in outside plant
applications to connect equipment and cables, or to cross-connect cables.
Most optical fiber connectors are spring-loaded, so the
fiber faces are pressed together when the connectors are mated. The resulting
glass-to-glass or plastic-to-plastic contact eliminates signal losses that
would be caused by an air gap between the joined fibers.
Every fiber connection has two values:
Attenuation or insertion loss
Reflection or return loss.
Measurements of these parameters are now defined in IEC
standard 61753-1. The standard gives five grades for insertion loss from A
(best) to D (worst), and M for multimode. The other parameter is return loss,
with grades from 1 (best) to 5 (worst).
A variety of optical fiber connectors are available, but SC
and LC connectors are the most common types of connectors on the
market.[citation needed] Typical connectors are rated for 500–1,000 mating
cycles.[2] The main differences among types of connectors are dimensions and
methods of mechanical coupling. Generally, organizations will standardize on
one kind of connector, depending on what equipment they commonly use. Different
connectors are required for multimode, and for single-mode fibers.
In many data center applications, small (e.g., LC) and
multi-fiber (e.g., MTP) connectors are replacing larger, older styles (e.g.,
SC), allowing more fiber ports per unit of rack space.
Features of good connector design:
Low insertion loss
High return loss (low amounts of reflection at the
interface)
Ease of installation
Low cost
Reliability
Low environmental sensitivity
Ease of use
Outside plant applications may require connectors be located
underground, or on outdoor walls or utility poles. In such settings, protective
enclosures are often used, and fall into two broad categories: hermetic
(sealed) and free-breathing. Hermetic cases prevent entry of moisture and air
but, lacking ventilation, can become hot if exposed to sunlight or other
sources of heat. Free-breathing enclosures, on the other hand, allow
ventilation, but can also admit moisture, insects and airborne contaminants.
Selection of the correct housing depends on the cable and connector type, the
location, and environmental factors. Careful assembly is required to ensure
good protection against the elements.
Depending on user requirements, housings for outside plant
applications may be tested by the manufacturer under various environmental
simulations, which could include physical shock and vibration, water spray,
water immersion, dust, etc. to ensure the integrity of optical fiber
connections and housing seals.