Fiber Connector Introduction

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 The optical fiber
connector is a device for detachable (movable) connection between an optical
fiber and an optical fiber. It precisely connects the two end faces of the
optical fiber so that the light energy output by the transmitting fiber can be
coupled to the receiving fiber to the maximum extent. And to minimize the
impact on the system due to its intervention in the optical link, which is the
basic requirement of optical fiber connectors. To a certain extent, the optical
fiber connector also affects the reliability and performance of the optical
transmission system.

 

Optical
fiber connectors can be divided into common
silicon-based optical fiber single-mode and multi-mode connectors according to
different transmission media, as well as other optical fiber connectors such as
plastics as transmission media; according to the structure of the connector, it
can be divided into: FC , SC, ST, LC, D4, DIN, MU, MT, etc. various forms. Among
them, ST connectors are usually used for wiring equipment, such as optical
fiber distribution frames, optical modules, etc.; and SC and MT connectors are
usually used for network equipment. According to the shape of the fiber end
face, there are FC, PC (including SPC or UPC) and APC; according to the number
of fiber cores, there are also single-core and multi-core (such as MT-RJ).
Optical fiber connectors are widely used and have many varieties. In the actual
application process, we generally distinguish according to the structure of the
optical fiber connector.

 

Fiber optic connector

 

FC round with thread
(most used on patch panels)

ST snap-on round type

SC card-connected square
type (most used on router switches)

PC microsphere grinding
and polishing APC is 8 degree angle and do microsphere grinding and polishing

MT-RJ square type, a
dual-fiber transceiver (useful on Huawei 8850)

 

Optical fiber module:
generally supports hot swap, GBIC Giga Bit rate Interface Converter, the
optical fiber interface used is mostly SC or ST type SFP small package GBIC,
the optical fiber used is LC type.

 

Fiber Used: Single mode:
L, wavelength 1310, single mode long distance LH, wavelength 1310, 1550
Multimode: MM wavelength 850.

 

SX/LH means single-mode
or multi-mode fiber can be used.

 

In the label indicating
the pigtail connector, we can often see “FC/PC”, “SC/PC”,
etc., which have the following meanings The part in front of “/”
indicates the connector model of the pigtail.

 

The “SC”
connector is a standard square connector, using engineering plastics, which has
the advantages of high temperature resistance and not easy to oxidize. The
optical interface of the transmission equipment side generally uses the SC connector.

 

The LC connector is similar in shape to
the SC connector, but smaller than the SC connector.

 

The “FC”
connector is a metal connector, which is generally used on the ODF side. The
metal connector can be plugged in more times than plastic.

 

There are many types of
connector signals, in addition to the three introduced above, there are also
MTRJ, ST, MU, etc.

 

For the specific
appearance, see the following.

 

“/” indicates the
cross-section process of the optical fiber connector, that is, the polishing
method. “PC” is the most widely used in telecom operators’ equipment,
and its joint cross-section is flat. The attenuation of “UPC” is
smaller than that of “PC”, and it is generally used for equipment
with special needs. Some foreign manufacturers use FC/UPC for internal fiber
jumpers in ODF racks, mainly to improve ODF equipment’s own indicators.

 

In addition, the
“APC” model is widely used in radio and television and early CATV.
Its pigtail head uses an end face with an angle, which can improve the quality
of the TV signal. The main reason is that the TV signal is analog light
modulation. When the connector is coupled When the surface is vertical, the
reflected light returns along the original path. Since the unevenness of the
refractive index distribution of the fiber will return to the coupling surface
again, although the energy is small at this time, the analog signal cannot
completely eliminate the noise, so it is equivalent to superimposing a weak
signal with time delay on the original clear signal. It is ghosting on the
screen. The inclination of the pigtail headband can prevent the reflected light
from returning along the original path. Generally, this problem does not exist
in general digital signals.