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2021 Ultimate Guide of Fiber Patch Cords

Views:7     Author:Site Editor     Publish Time: 2021-06-02      Origin:Site

The fiber optic patch leads are used to make jumpers from equipment to optical fiber cabling links. It has a thicker protective layer and is generally used for the connection between the optical transceiver and the terminal box. It is applied in some fields such as optical fiber communication systems, optical fiber access networks, optical fiber data transmission, and local area networks.

 

1. What are fiber patch cords?

2. How are patch cords made/how to make patch cables?

3. Types of patch cords/fiber patch cord types

4. Main parameters of fiber patch cord

5. Features of fiber patch cord

6. What are patch cords used for?

7. How to check whether the fiber patch cord is qualified?

8. The precautions for the installation and use of fiber optic patch cable

9. How to choose fiber optic patch leads?

10. The difference between carrier-grade and network-grade fiber optic patch cable

 


fiber optic patch cable


1. What are fiber patch cords


The fiber optic patch cable (also known as optical fiber connector) means that both ends of the optical cable are equipped with connector plugs to realize the active connection of the optical path. Optical fiber patch cord/cable is similar to coaxial cable, except that there is no mesh shielding layer. Its center is the glass core through which light propagates. 

 

In a multimode fiber, the diameter of the core is 50μm~65μm, which is roughly equivalent to the thickness of a human hair. The single-mode fiber core has a diameter of 8 μm to 10 μm. The core is surrounded by a glass envelope with a lower refractive index than the core to keep the optical fiber in the core. On the outside is a thin plastic jacket to protect the envelope.

 

 

2. How are patch cords made/how to make patch cables


1) Fiber pretreatment: Strip fiber. 


As a professional fiber optic patch cord manufacturer and supplier, Dowell introduces professional fiber stripping tools, which are mainly aimed at peeling the coating layer and reducing the damage to the fiber cladding. For multi-mode fibers, this has little effect, but for single-mode fibers, the impact is relatively large. One of the parameters of the single-mode fiber is the mode field diameter, which means that the cladding of the single-mode fiber is to transmit a part of the optical signal. 

 

In theory, if the fiber cladding is damaged, the polarization mode dispersion and attenuation will increase. Actual test results, the impact is there, but not much. One thing to note is that by testing multiple fibers with damaged cladding. It is found that damage to the cladding will increase the possibility of fiber breakage during bending, and the attenuation of the 1550 wavelength will increase significantly during bending.

 

2) Fiber optic ferrule assembly.


Doing the ferrule assembly by yourself can reduce the cost by about 4-5 minutes per head. The ferrule adopts Japanese Seiko ceramic ferrule uniformly. Although the cost is high, its eccentricity is very good. 

 

There are two eccentricities (concentricity), one is the optical fiber itself, and the other is the ferrule. A simple method can be used to preliminarily judge the quality of the ferrule. Insert the fiber into the ferrule, and then lift the fiber upside down to see if the ferrule slips from the fiber. A good ferrule will not slip off the fiber.

 

3) Glue injection preparation


Before grinding, it is mainly for the treatment of glue and ferrule. The first is the choice of glue. Most fiber patch cord factories have chosen 353ND (epoxy glue). This glue is easy to use. After the ratio of 10:1 is good, it is rotated at a high speed to throw out the bubbles, which avoids the change of the fiber stress due to temperature changes in the future, which will cause the fiber to bend and increase the attenuation.

 

fiber patch cords


4) Ferrule injection


The injection is based on a slight exposure of the front end of the ferrule. The equipment introduced this time for the simultaneous injection of multiple ferrules has very precise control of the amount of glue and a very fast speed. The cheap optical fiber patch cords sold in Zhongguancun are basically not glued injection, but optical fiber optical glue, which will cause problems such as easily fall off of the optical fiber head and bending of the optical fiber.

 

5) Glue curing


Insert the optical fiber into the ferrule with glue, and then put it into the curing oven for curing. Generally, the curing temperature of the colloid is 80-90 degrees, and the time is about 60 minutes. In order to increase the output, the temperature can also be increased to about 150 degrees, and the time is about 10 minutes. Because the temperature difference between the inside and outside of the colloid is too large, the stress generated by the colloid is difficult to control. It is impossible to estimate what kind of changes the optical fiber will produce, and it may affect the optical fiber itself.

 

3. Types of patch cords/fiber patch cord types

 

1) Fiber optic patch leads can be divided into common silicon-based optical fiber single-mode and multi-mode jumpers according to different transmission media, and other fiber patch cords such as plastics as the transmission medium.

 

①Single-mode fiber patch cord

Generally, the fiber optic patch cable is indicated by yellow, the connector and protective cover are blue, and the transmission distance is longer.

 

② Multi-mode fiber patch cord

Generally, the fiber optic patch lead is indicated by orange, and some are indicated by gray. The connector and protective cover are beige or black, and the transmission distance is short.

 

 

The difference between single-mode and multi-mode fiber patch cord

 

In the field of optical fiber data transmission, the term "mode" is used to describe the propagation mode of optical signals in the fiberglass core. That is, the mode is the propagation path of light. Therefore, in a single-mode fiber, light travels along one path; in multi-mode fiber, light travels in multiple paths.

 

①In appearance

The sheath of single-mode fiber patch cables is generally yellow, while the multi-mode is generally orange or so-called aqua (the color between blue and green). In terms of core diameter, multi-mode is generally slightly thicker.

 

1


② Transmission distance

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

 

2


③ In terms of the light source

LED light source is relatively scattered and can produce multiple modes of light, so it is mostly used for a multi-mode fiber patch cable. The laser light source is close to a single mode, so it is usually used for single-mode fibers.

 

3


④ Bandwidth

Single-mode fiber has a higher bandwidth than multi-mode fiber (As I said before, bandwidth refers to the frequency at which data is sent, so the adjective "higher" is used).

 

4


⑤ Usage cost

Multi-mode fiber allows multiple optical modes to pass, so multi-mode 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 a multi-mode fiber. Therefore, the use cost of a single-mode fiber is much higher than that of a multi-mode fiber.

  

2) Fiber patch cords can be divided into FC fiber patch cable, SC fiber patch cord, ST fiber optic patch leads, LC fiber optic patch cable, MTRJ fiber optic patch cable, MPO fiber optic patch leads, MU fiber patch cords, SMA fiber patch cord, FDDI fiber patch cable, E2000 optic patch cable, DIN4 fiber optic patch leads, D4 fiber optic patch cable, etc. various forms. The more common fiber optic cords can also be divided into FC-FC, FC-SC, FC-LC, FC-ST, SC-SC, SC-ST, etc.

 

 

① LC fiber patch cable

Developed by BELL Research Institute, the connector is similar to SC but smaller than SC. It uses a modular jack latch that is easy to operate. The size of the pin and sleeve is 1.25mm, which is half of the size used by ordinary SC and FC. The connector for connecting the SFP optical module is often used in routers. To a certain extent, the density of optical fiber connectors in the optical fiber distribution frame can be increased.


lc patch cord


② SC fiber optic patch lead

Developed by the Japan NTT company, the structure and size of its pin and coupling sleeve are exactly the same as FC type. Standard square connector, fasten with plug-in latch type lock, no need to rotate. It is often used as a connector for GBIC optical modules and is often used in routers and switches. It has the characteristics of low price and low fluctuation of access loss. Commonly used for 100G BASE-FX connection.


sc patch cord


③ FC patch cord

It was first developed by the NTT of Japan. FC is the abbreviation of Ferrule Connector in English. The outer protective sleeve is a metal sleeve, and the fastening method is a turnbuckle, which is generally used on the ODF side (most used on the distribution frame). The FC patch cord connector is generally used in telecommunication networks and has a nut screwed to the adapter. The advantage is that it is reliable and dustproof, but the disadvantage is that the installation time is slightly longer.


fc patch cord


④ ST optical patch cord

The outer shell is round, and the fastening method is turnbuckle, which is often used in optical fiber distribution frames. The fiber core is exposed, and a bayonet is fixed after the plug is inserted and rotated half a circle. For the 10Base-F connection, the connector is usually ST type.


st patch cord


⑤ MPO (multi-fiber push-on) fiber jumper

One of the MT series connectors, two guide holes with a diameter of 0.7mm on the left and right sides of the ferrule are accurately connected with the guide pin (also called PIN pin). Various forms of MPO jumpers can be produced after processing MPO connectors and optical fiber cables.


mpo patch cords


⑥ MT-RJ type optical fiber patch cord

A square fiber optic connector for the transceiver. The MTRJ type optical fiber jumper is composed of two high-precision plastic molded connectors and optical cables. The outer parts of the connector are precision plastic parts, including a push-pull plug-in clamping mechanism. Suitable for indoor applications in telecommunication and data network systems.

 

MT-RJ started with the MT connector developed by NTT, with the same door lock mechanism as the RJ-45 LAN electrical connector. The optical fiber is aligned with the guide pins installed on both sides of the small sleeve to facilitate the connection with the optical transceiver. The connector end face fiber is a dual-core (spaced arrangement design, which is a next-generation high-density fiber optic connector mainly used for data transmission.

 

⑦ Biconic Connector

The most representative product in this type of optical fiber connector was developed by Bell Labs in the United States. It consists of two precision-molded cylindrical plugs with frusto-conical ends and a coupling assembly with a double-cone plastic sleeve inside.

 

⑧ DIN47256 optical fiber connector

This is a connector developed by Germany. The structure size of the pin and coupling sleeve used in this connector is the same as that of the FC patch cord, and the end face treatment adopts the PC grinding method. Compared with the FC patch cord, its structure is more complicated. The internal metal structure has a spring to control the pressure, which can avoid damage to the end surface due to excessive insertion pressure. In addition, the mechanical precision of this connector is high, so the insertion loss value is small.

 

⑨ MU type connector

MU (Miniature unit Coupling) connector is the world's smallest single-core optical fiber connector developed by NTT based on the most used SC connector at present. The connector uses a diameter sleeve and a self-retaining mechanism, and its advantage is that it can achieve high-density installation. Using the MU diameter sleeve, NTT has developed the MU connector series. 

 

They have socket type connectors (MU-A series) for optical cable connection; backplane connectors with self-holding mechanism (MU-B series) and simplified sockets for connecting LD/PD modules and plugs (MU-SR series) Wait. With the rapid development of optical fiber networks towards greater bandwidth and greater capacity and the widespread application of DWDM technology, the demand for MU connectors will also grow rapidly.


 

4. Main parameters of fiber patch cord

 

 

Product type

ST

SC

FC


Multi-mode

Single-mode

Multi-mode

Single-mode

Multi-mode

Single-mode

Insertion loss

≤0.2dB

≤0.2dB

≤0.2dB

≤0.2dB

≤0.2dB

≤0.2dB

Return Loss

PC≥45 dB

PC≥45dB

UPC≥50dB

PC≥45dB

UPC≥50dB

PC≥45dB

UPC≥50dB

PC≥45 dB

UPC≥50dB

PC≥45 dB

UPC≥50 dB

Repeatability

≤0.2dB

≤0.2dB

≤0.2dB

≤0.2dB

≤0.2dB

≤0.2dB

Interchangeability

≤0.2dB

≤0.2dB

≤0.2dB

≤0.2dB

≤0.2dB

≤0.2dB

Temperature range

-40ºC~85 ºC

-40ºC~85 ºC

-40ºC~85 ºC

-40ºC~85 ºC

-40ºC~85 ºC

-40ºC~85 ºC


Product type

MT-RJ

LC


Multi-mode

Single-mode

Multi-mode

Single-mode

Insertion loss

≤0.2dB

≤0.2dB

≤0.2dB

≤0.2dB

Return Loss

PC≥45 dB

UPC≥50 dB

APC≥65 dB

PC≥45 dB

UPC≥50 dB

APC≥65 dB

PC≥45 dB

UPC≥50 dB

APC≥65 dB

PC≥45 dB

UPC≥50 dB

APC≥65 dB

Repeatability

≤0.2dB

≤0.2dB

≤0.2dB

≤0.2dB

Interchangeability

≤0.2dB

≤0.2dB

≤0.2dB

≤0.2dB

Temperature range

-40ºC~85 ºC

-40ºC~85 ºC

-40ºC~85 ºC

-40ºC~85 ºC



5. Features of fiber patch cord


1) Low insertion loss

2) Good repeatability

3) Large return loss

4) Good inter-plug performance

5) Good temperature stability

6) Strong tensile performance

 

 

6. What are patch cords used for?


Optical fiber patch cord products are widely used in: communication rooms, fiber to the home, local area networks, fiber optic sensors, fiber optic communication systems, fiber optic connection transmission equipment, national defense combat readiness, etc. It is suitable for cable television networks, telecommunication networks, computer optical fiber networks, and optical test equipment. The subdivision is mainly used in several aspects.

 

1) Optical fiber communication system

2) Optical fiber access network

3) Optical fiber data transmission

4) Fiber CATV

5) Local Area Network (LAN)

6) Test equipment

7) Fiber optic sensor

 

Optical fiber patch cords provide interconnection and cross-interconnection applications in the network connection of access equipment and are generally widely used in telecommunications equipment rooms and data centers. They are available in OM4, OM3, OM2, OM1, and OS1/OS2 optical fiber types, which can meet the requirements of Gigabit Ethernet, 10 Gigabit Ethernet, and high-speed fiber channel network connections.

 

Fiber patch cords are usually used to connect the ports of the fiber distribution frame. It mainly supports network applications in the level and scattered areas of equipment and meets the wiring requirements. Support a variety of outer sheath materials such as conventional, flame-retardant, low-smoke, and halogen-free. In addition, fiber optic patch cords also support high-speed communications, and can also be used in many fields, such as integrated optics, laser detection and display, and material processing.

 

7. How to check whether the fiber patch cord is qualified?

 

First, use a light pen to test whether the jumper is light, make sure the fiber is not broken, and measure the index. General carrier-grade indicators: Insertion loss is less than 0.3dB, and return loss is greater than 45dB.

 

The performance test of fiber optic patch leads is divided into:

 

1) Optical performance testing, including return loss/insertion loss testing. The test instrument can use FibKey 7602 return loss/insertion loss integrated tester.

 

2) End face geometry test, the parameters tested include the radius of curvature, vertex offset, fiber height, etc. The test instrument is an interferometer, and many people use NorlandAC/NC3000 or CC6000 for testing. Especially the CC6000 interferometer is used in more and more factories because of its superior cost performance.

 

China fiber optic patch cord supplier


3) Scratch detection on the fiber end face. Use a video optical fiber magnifying glass for observation. For example, many factories use FibView FV-400PA for inspection. The instrument can give the clearest images, and the operation is extremely simple. Some customers also use FibKey-5600 variable magnification magnifying glass for inspection. This instrument integrates 400 times, 200 times, and 80 times magnifiers, which can clearly and conveniently observe the condition of the fiber end face and the ferrule end face. Of course, you can also use related software for automatic inspection.

 

4) Optical fiber tensile test, need to test the tensile force that the optical fiber connector can withstand.

 

5) Ambient temperature experiment, it is necessary to test the performance index of the optical fiber connector under different ambient temperature conditions.

 

 

8. The precautions for the installation and use of fiber optic patch cable


1) The transceiver wavelengths of the optical modules at both ends of the fiber jumper must be the same. That is to say, both ends of the fiber must be optical modules of the same wavelength. The simple way to distinguish is that the colors of the optical modules must be the same. 

 

In general, short-wave optical modules use multimode optical fibers (orange optical fibers), and long-wave optical modules use single-mode optical fibers (yellow optical fibers) to ensure the accuracy of data transmission.

 

2) Before use, the ceramic ferrule and the end face of the fiber patch cord must be wiped clean with alcohol and absorbent cotton.

 

3) When the optical fiber is installed, insert and unplug gently. Excessive force can easily cause the optical fiber ferrule to shift, thereby affecting the quality of optical communication.

 

4) Do not over-bend and loop the optical fiber during use, as this will increase the attenuation of the light in the transmission process.

 

5) After using the optical fiber jumper, be sure to use a protective cover to protect the optical fiber connector. Dust and oil will damage the coupling of the optical fiber.

 

6) Do not look directly at the end face of the optical fiber during laser signal transmission.

 

7) If the optical fiber connector is dirty, you can clean it with a cotton swab dipped in alcohol. Otherwise, it will affect the communication quality.

 

8) Ensure that it is used within the working temperature: -40℃~+80℃, relative humidity: 5%~90%.

 

9) When there is damage caused by man-made or other force majeure, the damaged fiber jumper should be replaced in time.

 

10) Read the manual carefully before installation, and install and debug under the guidance of the manufacturer or dealer’s engineer.

 

11) If there is an abnormal situation in the optical fiber network or system, the troubleshooting method can be used to test one by one. When testing or troubleshooting jumper faults, you can do a continuity test first. Generally, a visible laser pointer can be used to judge the lighting of the entire optical fiber link. Or further use a precision optical fiber insertion loss return loss tester to test its various indicators. If the indicators are within the qualified range, the fiber optic patch cable indicates normal, otherwise, it is unqualified.

 

 

9. How to choose fiber optic patch leads?

 

Step 1: Choose the correct connector type (LC / SC / ST / FC / MPO / MTP)

Different connectors are used to plug in different devices. If the ports of the two devices are the same, we can use LC-LC / SC-SC / MPO-MPO jumpers. If you want to connect devices with different port types, LC-SC / LC-ST / LC-FC jumpers may be suitable for you.

 

Step 2: Choose single-mode or multi-mode fiber optic cable type?

Single-mode fiber patch cords use 9/125um fiber, and multi-mode fiber patch cords use 50/125um or 62.5/125um fiber. Single-mode fiber jumpers are mainly used for long-distance data transmission. Multimode fiber optic patch leads are mainly used for short-distance transmission. The sheath of general single-mode fiber jumpers is yellow, while the sheath of multi-mode fiber jumpers is orange or blue.

 

Step 3: Choose simplex or duplex fiber optic cable type?

Simplex means that this fiber optic patch cord has only one fiber optic cable and only one fiber optic connector at each end, which is used for bidirectional (BIDI) optical modules. Duplex can be seen as two fiber jumpers side by side, used for ordinary optical modules.

 

Step 4: Choose the correct jumper length (1m / 5m / 10m / 20m / 30m / 50m)

The length of the fiber jumper is different, usually 0.5m to 50m. You should select the appropriate cable length according to the distance between the devices to be connected.

 

Step 5: Choose the correct connector polishing type (UPC / APC)

Since the loss of the APC connector is lower than that of the UPC connector, the optical performance of the APC connector is generally better than that of the UPC connector. In the current market, APC connectors are widely used in applications that are more sensitive to return loss such as FTTx, Passive Optical Network (PON), and Wavelength Division Multiplexing (WDM). 

 

fiber optic patch leads


But APC connectors are usually more expensive than UPC connectors, so you should consider whether you need APC connectors according to your actual situation. For those applications that require high-precision optical fiber signals, APC should be the first consideration, but other less sensitive systems will also perform well using UPC. Generally, the color of the fiber jumper using an APC connector is green, and the color of using a UPC connector is blue.

 

Step 6: Choose the correct sheath (PVC / LSZH / OFNP / armored)

Generally, there are three types of jumper sheaths: PVC, LSZH, OFNP. The jumper sheath made of PVC material is common to everyone, with average fire resistance and the lowest price. LSZH jumper sheath is made of low-smoke and halogen-free materials, which are environmentally friendly and flame-retardant, but the price is more expensive. OFNP jumper the wire sheath refers to the American Fire Protection Commission standard, which can be flame retardant. 

 

This material will automatically extinguish when it leaves the fire source. It is the most expensive and suitable for large data centers. You can choose according to your own situation. In addition to the above three jumpers, there is another type of armor. Its steel sleeve structure can well protect the fragile optical fiber, and the bending resistance is relatively strong. Such fiber optic patch leads can withstand higher pressure, so they are suitable for routing along the floor and other areas that may be trampled on. This kind of optical fiber optic patch cords also has the advantages of strong abrasion resistance, resistance to pull, and anti-rat bite.

 

10. The difference between carrier-grade and network-grade fiber optic patch cable

 

1) What is a carrier-grade fiber optic patch cord?

Telecom-grade optical patch leads are a kind of jumper, usually has a thicker protective layer, and is generally used for quality inspection connection between optical transceivers and terminal boxes. In multi-mode telecom-grade patch cords, the core diameter is about the same as the thickness of a human hair, which is 15-50 µm, while the diameter of single-mode telecom-grade fiber patch cords is 8-10 µm. The core is covered with a glass envelope with a lower refractive index than the core for protection, and a thin plastic envelope is outside.

 

2) What is a network-level fiber patch cord?

The attenuation of network-level jumpers is larger than that of telecom-level fiber patch cords, and its attenuation is generally greater than 0.2db, and data packet loss may occur during transmission.

 

3) What are the differences between telecom-level jumpers and network-level fiber optic patch leads?

 

① Attenuation

Telecom-grade fiber optic jumpers have less attenuation than network-grade fiber optic jumpers, and the transmission data is more stable and not easy to lose.

 

② Grinding times

The polishing process of carrier-grade fiber optic patch cords is generally 5 times, and that of network-grade fiber optic patch cords is 4 times.

 

③ Price

The price of carrier-grade fiber optic patch cords is higher than that of network-grade fiber optic patch cords.

 

④ Market demand

The market demand for telecom-level jumpers is greater than that of network-level fiber optic cable patch cords.

 

Dowell is China top 10 fiber optic patch cord supplier and manufacturer, offering professional fiber optic patch cable knowledge and high-quality fiber patch cords. If you have any needs, please contact us!


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