What are Fiber Optic Patch Cables?

11 February 2022

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Hello everyone, I am Rose. Today I will introduce fiber optic patch cables to you. Optical fiber communication, as an emerging technology, has become one of the main pillars of modern communication and plays a critical role in modern telecommunication networks, thanks to the rapid growth of traffic data.

Ⅰ. What are fiber optic patch cables?

Fiber optic patch cables are defined as fiber optic cables having connector plugs on both ends and a thicker protective coating. It is primarily utilized in optical fiber communication systems, optical fiber access networks, optical fiber data transmission networks, and local area networks, among other applications. It can be used in cable television networks, communications networks, computer optical fiber networks, and optical test equipment.

Ⅱ. The structure of fiber optic patch cables

Fiber optic patch cables are identical to coaxial cables in structure, with the exception that fiber jumpers do not have a mesh shielding layer and the center is a glass core for light propagation. A glass envelope surrounds the core, followed by a thin plastic jacket (PVC or Teflon) on the outside.

It's crucial to understand the distinction between fiber patch cords and pigtails. The pigtail has only one end with a connector plug, while the other end is a broken end of a fiber optic cable core that is fusion spliced to other fiber optic cable cores. Couplers, jumpers, and other similar devices are also employed). The jumper has moveable connectors on both sides. Interfaces come in a variety of shapes and sizes. Different couplers are required for different interfaces. The jumper has two sections and can be worn as a pigtail.

Ⅲ. Types of fiber optic patch cables

There are many different types of fiber optic patch cables (also known as optical fiber connectors), which are optical fiber connections attached to optical modules. They cannot be used together. The LC  fiber optic connector is used for the  SFP  module, while the SC  fiber optic connector is used for the  GBIC . A full overview of some commonly used optical fiber connectors in network engineering is provided below:

①FC type fiber optic patch cables: A metal sleeve is used for external strengthening, and a turnbuckle is used for fastening. On the  ODF  side, it's commonly used (the most used on the patch panel)

②SC type fiber optic patch cables: The connector connecting the  GBIC optical module has a rectangular shell and a plug-and-pull fastening technique that does not need rotation. (Most commonly found on router switches)

③ST-type fiber optic patch cables: The exterior shell is circular, and the attaching method is turnbuckle, which is often used in optical fiber distribution frames. (Standard ST connectors are used for  10Base-F  connections.) Fiber optic distribution frames are frequently made of this material.)

④LC-type fiber optic patch cables: It's a connector for joining  SFP modules that uses an easy-to-use modular jack (RJ) latch mechanism. (This is a term widely used by routers)

According to the connector, it can be divided into FC, ST, SC, LC, MU, MPO/MTP, E2000, MTRJ,  SMA, etc. The end-face contact methods include  PC, UPC, APC, and the connectors used to connect optical modules are mainly LC.  SC.  These three kinds of MPO/MTP. Optical fiber jumper connectors are a problem that users must consider when purchasing optical fiber jumpers.

According to the color of the connector, it can be divided into: blue (commonly used for single-mode connectors), beige, and gray (commonly used for multi-mode connectors).

According to the color of the tail cover, it can be divided into: gray, blue, green, white, red, black, turquoise.

According to the number of fiber cores, it can be divided into single-core, double core, 4 cores, 6 cores, 8 cores, 12 cores, 24 cores, 48  cores, and 72 cores or as specified by customers.

According to the diameter of the core, it can be divided into multimode fiber and single-mode fiber. 50μm-65μm is a multi-mode fiber, which refers to a fiber that transmits multiple modes at a given operating wavelength, with large dispersion loss and short transmission distance, and is suitable for short-distance optical fiber communication systems. 9μm is a single-mode fiber, which can only transmit light of one mode, and its intermodal dispersion is very small, which is suitable for long-distance communication.

According to the  ITU-T  standard, communication fibers are divided into seven categories:  G.651, G.652, G.653, G.654,  G.655, G.656, and  G.657, of which  G.651 is a multimode fiber. G.651-G.657 are single-mode fibers.  ISO/IEC  divides multimode fibers into OM1-OM5. These five types of multimode fibers are mainly used in local area networks (LANs) and data centers (DCNs). The fiber jumpers mentioned above, ETU-LINK ) are available.

The fiber length can be customized according to customer requirements.

According to the cable outer sheath material, it can be divided into ordinary type, ordinary flame-retardant type, low-smoke halogen-free type (LZSH), low-smoke halogen-free flame-retardant type, armoring, etc. The armored jumper is a new type of fiber optic patch cable that can be utilized in the equipment room or in other hazardous situations. Armored patch cables strengthen the protection of stainless steel hoses and have stronger compressive and tensile qualities than standard fiber optic patch cords.

Ⅳ. How to choose fiber optic patch cables?

OM1, OM2, OM3, OM4 multimode, and OS2 single-mode optical fibers are commonly found in fiber optic patch connections. SC, ST, FC, LC, MTRJ, and E2000 are some of the optical fiber jumper connector kinds. In practice, there is no one-size-fits-all solution, and you must choose based on your own needs. What factors should you consider while selecting a jumper for your network? Simply follow these simple instructions.

1. Types of fiber optic connectors

Different connectors are used for different devices, mainly MPO, SC.  FC, LC.  ST interface jumpers:

(1) MPO type fiber optic patch cables: used for 40G, 100G optical module connection and high-density data center;

(2) LC fiber optic patch cables: used for the connection of SFP optical modules, it uses modular jacks, and this kind of jumper is generally used on routers;

(3) SC-type fiber optic patch cables: It is connected to the GBIC optical module. Its shell is rectangular, and the fastening method is a plug-in latch type, which does not need to be rotated. It is generally used in routers and switches;

(4) FC type fiber optic patch cables: the external strengthening method adopts metal sleeve, and the fastening method is turnbuckle, which is generally used on the distribution frame;

ST-type fiber optic patch cables: the shell is round, and the fastening method is turnbuckle, which is generally used on the distribution frame.

2. Fiber Type

Multi-mode fiber optic patch cables use 50/125um or 62.5/125um fiber, while single-mode fiber optic patch cables use 9/125um fiber. Long-distance data transmission is handled by single-mode fiber optic patch cables, whereas short-distance data transmission is handled by multi-mode fiber optic patch cables. The jacket of single-mode fiber optic patch cables is yellow, while multi-mode fiber optic patch cables are classified as OM2 (orange), OM3 (water blue), OM4 (purple), and OM5 (orange) (apple green).

3. Connector grinding method

The optical fiber transmission quality is determined by different grinding procedures; PC/UPC is blue, while APC  is green.

PC (Physical Contact) is the abbreviation for physical contact. The ferrule's surface is ground into a small spherical shape, and the fiber core is situated at the highest point of bending, reducing the air gap between the fiber components and bringing the two fiber end faces into physical touch.

The ultra-physical end face is referred to as UPC  (Ultra Physical Contact). The UPC  connector's end face isn't fully flat, but it does have a little curve for more exact mating. UPC  is based on PC, but with better end surface polishing and surface gloss, and a more dome-shaped end surface.

The fiber end face is commonly honed to an 8° bevel in APC  (Angled Physical Contact), bevel physical contact. By reflecting light through its bevel angle to the cladding rather than directly back to the source, the 8° angled bevel enables for tighter fiber end faces and greater connection performance.

The insertion loss of PC, UPC., and APC  connectors is typically less than 0.3dB; however, because of the narrower air gap, UPC  /PC connectors are easier to achieve low insertion loss. APC  industry-standard return loss is -60dB,  PC return loss is -45dB, UPC  return loss is often -50dB (or even more), and PC return loss is -45dB.

4. The fiber optic patch cables protective sleeve material

PVC and  LSZH  are commonly used in fiber optic patch cords.

LSZH (Low Smoke Zero Halogen) is a low-smoke halogen-free material with good environmental protection and flame retardant properties, but it is relatively expensive. PVC  (Polyvinyl chloride) polyvinyl chloride material is flammable and produces toxic gas, so it is not suitable for indoor application, and the price is low.

When choosing fiber jumpers, it's also important to think about how long we'll be wearing them. When choosing fiber optic patch cables, we must consider not only the material's reliability but also the transmission rate and loss, as well as the specific parameter information.

The end face of the ferrule should be shielded to avoid bumps while utilizing fiber optic patch cables, and the dust cap should be applied promptly after disassembly. During transmission, the laser signal should not stare straight at the fiber's end face.

Ⅴ. Precautions for the use of fiber optic patch cables

Note on the use of fiber optic patch cables: (including single-mode fiber jumpers and multi-mode fiber jumpers)

1 The optical modules' transceiver wavelengths must match: the optical modules' transceiver wavelengths at both ends of the fiber jumper must match. The most common technique of differentiation is to compare the color of the fiber jumper.

2 Unless stated otherwise. Orange multimode fiber is used in the short-wave optical module. Yellow single-mode fiber is used in the long-wave module. This is a common misconception because it is contingent on the manufacturer's configuration. This is done to ensure data transfer correctness.

3 Because the fiber optic patch cord is made of sensitive material, it should not be bent or wrapped excessively during use. Pay attention to the protective cover, even if it is present. It is not only easy to destroy, but it will also enhance the amount of light transmitted. Attenuation is a term used to describe the process of reducing the intensity of

4 Fiber Optic Patch Cable Protection: The optical fiber coupling will be damaged if it is not dust- and oil-proof after it has been connected.