What Types of Fiber Optic Patch Cords Are There? What is the Difference Between Them?

Optical optic patch cords mean that the connector plugs are installed on both ends of the optical cable to realize the active connection of the optical path; one end with a plug is called a pigtail.

Fiber optic patch cords are similar to coaxial cables, except that there is no mesh shield, and the center is a glass core where light travels. In a multicore fiber, the diameter of the core is 50 μm to 65 μm, which is roughly the thickness of a human hair. The diameter of the single-mode fiber core is 8 μm~10 μm. The core is surrounded by a glass envelope with a lower refractive index than the core to keep the fiber within the core. On the outside is a thin plastic jacket that protects the envelope.

1. Common fiber optic patch cord types

1) LC fiber optic patch cord

The linker is similar to SC and smaller than SC. With easy-to-operate modular jack latches, the pin and sleeve size is 1.25mm, which is half the size used for common SC and FC. Connecting SFP optical modules, commonly used in routers, can improve the density of fiber optic patch cords in the optical fiber distribution frame to a certain extent.

2) SC fiber optic patch cord

The structure and size of its pins and coupling sleeves are exactly the same as those of the FC type. The standard square connector, the fastening method of the plug-in latch type lock, does not need to be rotated, and is often used as the connector of the GBIC optical module, which is often used in routers. It has the characteristics of low price and small fluctuation of access loss. Commonly used for 100G BASE-FX connection.

3) FC fiber optic patch cord

FC is the abbreviation of Ferrule Connector in English. The outer protective cover is a metal sleeve and the fastening method is a turnbuckle. It is generally used on the ODF side, and is used most on the patch panel. It has the advantages of strong fastening and anti-dust.

4) ST fiber optic patch cord

The outer shell is round, the fastening method is turnbuckle, the fiber core is exposed, and the plug is inserted and rotated half a circle to fix it with a bayonet. Often used as a 10BASE-F connector, it is mostly used in fiber optic distribution frames.

5) The MPO fiber optic pm fiber patch cord connector is one of the MT series connectors. The two guide holes with a diameter of 0.7mm on the left and right of the ferrule end face are precisely connected to the guide pin (also called PIN pin). MPO connectors and fiber optic cables can be processed to produce various forms of MPO patch cords.

2. The difference between single-mode and multi-mode fiber optic patch cords

The concept of single-mode and multi-mode is to classify fibers according to the propagation mode—the concept of multi-mode fiber and single-mode fiber propagation mode. In the field of fiber optic data transmission, the term "mode" is used to describe how an optical signal propagates within the fiber's glass core—that is, a mode is the path that light travels. So, in single-mode fiber, light travels along one path; in multimode fiber, light travels in multiple paths.

1) Appearance

The sheath of single-mode fiber optic patch cords is generally yellow, while multi-mode is generally orange or so-called aqua green (that is, the color between blue and green); in terms of core diameter, multi-mode is generally less. thicker.

2) Transmission distance

The transmission distance of single-mode fiber is not less than 5km, which is generally used for long-distance communication; multi-mode fiber can only reach about 2km, which is suitable for short-distance communication in buildings or campuses.

3) Light source

Because the LED light source is relatively scattered and can generate multiple modes of light, it is mostly used in multi-mode fibers; while the laser light source is close to a single mode, so it is usually used in single-mode fibers.

4) Bandwidth

Single-mode fiber has higher bandwidth than multi-mode fiber.

5) Cost of use

Multimode fiber allows the passage of multiple modes of light, so multimode fiber is more expensive than single mode fiber. However, the single-mode fiber uses a solid-state laser diode as the light source, which is far more expensive than the light source equipment of the multi-mode fiber, so the cost of using the single-mode fiber is much higher than that of the multi-mode fiber.