Category Archives: Fiber Cabling

Overcome OTDR Dead Zone With Launch Fiber

OTDR is a popular fiber optic testing tool which can be used to test the fiber loss, and locate the faults in fiber optic links. However, the OTDR dead zone will affect the testing result and the application of OTDR. To overcome OTDR dead zone during fiber optic testing, launch fiber is being added between OTDR and optical fiber link under test. OTDR launch fiber comes in different types of packages. OTDR launch box and OTDR launch fiber ring are the most commonly used launch fibers.

Why Can Launch Fiber Overcome OTDR Dead Zone?

OTDR insert pulses of light into fiber optic link and measure the back reflection caused by fiber faults to locate the faults. If a long fiber link is required to be tested, a lot of optical power should be inserted into the optical fiber to make sure that the light can be seen at the other end. If powerful optical pulses are inserted into optical fiber, pulse width of the launched optical signal will be increased, which will cause the dead zone at a length of fiber and affect the testing result of OTDR. This dead zone might be hundreds or thousands meters long.

OTDR launch box

To minimize the affection of the OTDR dead zone during fiber optic testing. A length of long enough optical fiber is being added between the OTDR and the fiber under test. In this way, the OTDR dead zone will happen in this additional optical fiber. The launch fiber is actually a length of optical fiber which is long enough to cover the OTDR dead zone to increase the testing accuracy. Launch fiber is usually terminated with a connector on each end to connect the OTDR with the fiber link under test.

launch fiber

OTDR Test With Launch Fiber

OTDR launch fiber mainly has two designs, one is fiber ring design and the other is box design, separately known as launch fiber ring and OTDR launch box or OTDR dead zone box. The using of them is generally the same. Here offer two situations about how to use OTDR launch fiber.

OTDR testing with launch fiber

In some cables, launch cable is being used to cover the dead zone at the beginning of the fiber link. In these cases, OTDR launch fiber or OTDR launch box is deployed between the OTDR and the near end connection as shown in the above picture. This allows the accurate measurement of the fiber loss at the near end connection.

OTDR and launch fiber

In some cases, the fiber loss at the far end connection should also be tested. Then, the launch fiber can be installed added at the far end connection to work as a receive cable, as shown in the above picture.

Please note that the launch fiber you used for testing should have the same fiber types (OS2, OM1, OM2, OM3, OM4) as the optical fiber under test.

Conclusion

Using launch fiber to overcome OTDR dead zone is the choice in most cases, especially for long optical fiber testing. Let the OTDR dead zone occur in the launch cable to ensure the accurate testing result. Launch fiber is suggested to be added at the beginning and the end of the fiber optic link, if the light loss of the whole fiber link is required. If you want to need more specific details about OTDR launch box, kindly visit another article: Why Do You Need OTDR Launch Box

Which Fiber Optic Wall Plate Do You Use?

With the expansion of fiber optic network, fiber optic cables are widely deployed in buildings and houses to be closer to end users. In many cases, fiber optic cables are installed in-wall. And fiber optic wall plates are used to provide easier and safer connection between the feed cables and the fiber patch cables that are linked to the target devices. Customers should select the right types of fiber optic wall plate to ensure the performance and connection of the fiber links.

Size and Design of Fiber Optic Wall Plate

Fiber optic wall plates have different sizes. But the most commonly used fiber optic wall plates are with a size of 86mm*86mm. The design (orientation) of the fiber optic wall plate also varies according to different applications. There are mainly three designs: straight, box and angled which are shown in the following pictures.

straight fiber wall plate
box fiber wall plate
angled fiber wall plate

The straight fiber optic wall plates are most commonly used one in many offices and buildings. They can provide architectural design for in-wall and recessed installations. The box type fiber optic wall plates are usually used in FTTH applications to provide easy connecting environments and safe places for fiber patch cable storage. The angled fiber optic wall plate has better performance to decrease the bend loss cause the fiber patch cable would have a smaller bend radius after connected to these wall plates (as shown in the following picture).

Fiber Adapter Type of Fiber Optic Wall Plate

Fiber optic wall plate uses the fiber adapter installed on itself to provide the connection and disconnection for fiber optic cables. Thus, the selection of fiber adapter type on the wall plate is essential. There are fiber optic wall plates which installed with SC, LC, FC, ST, etc. Both simplex and duplex adapters are also available in the market. The fiber type and polishing type of the fiber optic adapters should also be considered if you want to choose the right one for your application.

Port Counts of Fiber Optic Wall Plate

Except the above mentioned factors, the port count that a fiber optic wall plate can provide should also be considered. The port count of fiber optic wall plate with a size of 86mm*86mm is usually ranging from one to four. For most FTTH box type fiber optic wall plate there are usually two ports, one for feed fiber cable, and one for fiber patch cable that is connected to the target device, which is shown in the following picture.

Same-Day Shipping Fiber Optic Wall Plates

After considering the size, design, fiber adapter type and port count of the fiber optic wall plate, you will roughly know which fiber optic connector is suitable for your applications. The following picture shows part of the commonly used fiber optic wall plates which are available for same-day shipping.

SC Simplex Fiber Optic Wall Plate 2-port SC Fiber Optic Wall Plate 4-port SC Fiber Optic Wall Plate
Single Port SC Simplex Fiber Optic Wall Plate 2-Port SC Simplex  Fiber Optic Wall Plate 4-Port SC Simplex Fiber Optic Wall Plate
LC duplex fiber optic wall plate 2-port LC duplex Fiber Optic Wall Plate 4-port-lc-wall-plate
Single Port LC Duplex Fiber Optic Wall Plate 2-Port LC Duplex  Fiber Optic Wall Plate 4-Port LC Duplex Fiber Optic Wall Plate

Kindly contact sales@fs.com for more details about fiber optic wall plate, if you are interested.

Source: Fiber Optic Wall Plate Selection Guide

How to Use Optical Power Meter

To ensure the signal transmission performance in fiber optic network, optical power should be well controlled. Optical power should not be too high or too low. And it should be within the scope of the device’s requirement. To achieve accurate measurement, optical power meter is usually used to test the optical power. But How to use optical power meter? This post will make an illustration of the power meter components and then state how to use optical power meter.

Buttons on Optical Power Meter

The functions and operation of optical power meters provided by the market are similar. Generally there are four buttons on the optical power meter: power button, dBm/w button, REF button and λ button. The functions of these buttons are listed in the following:

  • Power button: turn the power meter on or off;
  • dBm/w button: shift between linear (mW) mode and logarithmic (dBm) mode;
  • REF button: press this button to set the current measured power as the referent point;
  • λ button: select the calibrated wavelength. The most commonly used wavelengths are 850nm, 980nm, 1310nm, and 1550nm.

Here takes an example of a typical handheld optical power meter (FOPM-104) which is designed by FS.COM as shown in the following picture.how to use optical power meter: buttons

Adapter Type of Optical Power Meter

To use the optical power meter, a length of fiber optic patch cable is usually required to connect the optical power meter interface and the interface of devices requiring test. For instance, if the interface on the fiber optic power meter is FC, the device for testing has a LC interface. Then a length of FC-LC fiber patch cable is needed. Some of the optical power meters have only one fixed optical interface. Some can provide replaceable optical adapter to fit different patch cables. The above mentioned FOPM-104 handheld optical power meter provides three type adapters: SC, FC and ST (as shown in the following picture).optical power meter adapter

For testing of fiber optic interface like LC, SC, ST and FC, this above power meter is enough. Some optical power meter might have two optical interfaces for common connectors. However, interface like MTP/MPO, optical power meter with special interface should be used. The following picture shows a MTP optical power meter provided by FS.COM, which can be used to test devices or components with MTP interfaces like 40G SR4 QSFP+ transceiver.how to use optical power meter: adapter types

Optical Power Measurement Using Optical Power Meter

How to use optical power meter? It can be easy. The following video will take the example of 10G-LR SFP+ Cisco compatible module to illustrate how to use optical power meter for testing. This cisco compatible transceiver will be inserted in Cisco Nexus 9396PX switch. A length of single-mode LC-FC fiber patch cable is required. This is because 10G-LR SFP+ transceiver is a single-mode transceiver working on wavelength of 1310nm. After the optical power meter is connected to the module. Turn on the power button and press λ button to select 1310nm wavelength. At first the power value will change rapidly, then it slows down until still. The final power value will be shown on the screen.

Conclusion

This post introduces the buttons and adapter types of optical power meters, and illustrates how to use optical power meter with the aid of both text and video. Kindly visit Optical Power Meter page or contact sales@fs.com for more details.

Related Article: DWDM MUX/DEMUX Insertion Loss Test

                             Optical Power Meter (OPM): A Must for Fiber Cable Testing

Add More Beneficial to Fiber Patch Cables

More and more fiber optic cables are adding to the existing fiber optic network. Technicians are facing the challenges to detail with thousands or more fiber patch cables. Well organized fiber patch cable and fiber cabling system are no longer enough for the increasing need. The fiber patch cables used in data centers should still have reliable and stable performance under repeat connections and disconnections. To find the best solution for fiber patch cables in high density data center and server room. The most urgent current demands should be considered.

fiber cabling problems

How to Solve Fiber Cabling Problems

There are mainly two problems in data center for fiber cabling. One is too many fiber cables installed in limited spaces. The other one is the property of fiber optic cable which requires careful operation during cabling.

high density fiber cabling
Decrease Fiber Patch Cable Space Requirement With Uniboot Design

As more and more devices are added in data center, decrease fiber count in data center is not that easy. Thus, decrease the space requirement for each fiber optic patch cable is relatively easier. Decrease cable diameter is suggested. Smaller fiber cable diameter is preferred in data center now. New versions of duplex fiber patch cables like LC uniboot fiber patch cables are invented. The following picture shows one end of the LC uniboot fiber patch cable. This type of duplex fiber cable has a smaller cable diameter than that of traditional duplex zipcord fiber cable. And the uniboot design has lower space requirement for connector boot.

LC uniboot fiber patch cable
Provide Easier Finger Access With Push Pull Tab

However, even the sizes of the fiber cable and connector boot are decreased. The port type like LC, SC and MTP cannot be changed directly. There is still finger access problem at the device port is the devices like switches and fiber enclosure are fully loaded with fiber patch cables. Then a push pull tab is being added to the connector body. The following picture shows the details of LC uniboot fiber patch cable with push-pull tab.

LC push-pull fiber patch cable

With the help of this small but useful push-pull tab, data center technicians not only have easier access to every port, but also enjoy easier connecting and disconnecting of every individual fiber patch cable in high density cabling environment without affecting any other fiber links near it. There is also high density push-pull MTP-LC breakout cable available in FS.COM.

push-pull MTP-LC fiber patch cable
Use Bend Insensitive Fiber Cable for Flexible Cabling

Data center technicians are required to operate the fiber patch cables very carefully to decrease the bend loss. The using of bend insensitive fiber cable can offer a much flexible and easy cabling environment for the data center technicians. The worrying of bend loss can be eliminated.

bend insensitive fiber patch cable

All Benefits in One Fiber Patch Cable

As the above mentioned, to build a high density cabling environment, uniboot fiber patch cable and high density push-pull tab fiber patch cables are being invented. To offer an easier and flexible cabling environment with high performance, bend insensitive fiber cables are suggested. What if we add all these great advantages into a single length of fiber patch cable? Here introduces the very special but useful LC bend insensitive uniboot fiber patch cable with push-pull tab (shown in the following picture).

LC bend insensitive uniboot fiber patch cable

This LC uniboot fiber patch cable has all the above mentioned advantages for space saving, easy finger access and flexible cabling with lowest bend loss. These LC uniboot fiber patch cables of different fiber types and cable lengths are available in FS.COM. If you are looking for some fiber patch cables to add more beneficial to your data center, you can consider this LC Push-Pull bend insensitive uniboot fiber patch cable.

12-Fiber MTP Cabling System

MTP fiber cables and related components are now widely deployed in high speed fiber optic transmission system. MTP cables really provide great performance during 40G and 100G transmission over both short and long transmission distances. But there are so many types of MTP components like MTP cables, MTP cassettes, MTP adapters, MTP patch panels, etc. And all of these products are available in different MTP polarity types. Customers can get confused easily by these MTP products.

12-fiber MTP trunk cable

In addition, unlike traditional duplex transmission on two fibers or BiDi transmission over a single fiber, MTP system transmits optical signal over 12, 24 or more fibers at the same time. More fibers and cables are employed in MTP cabling system. Thus, technicians in data center or server room are still facing a headache problem which is MTP cable management. This post is to offer the details of a commonly used MTP cabling system—12-fiber MTP cable system for better understanding, selecting and management of MTP products.

12-Fiber MTP Cabling Applications

The 12-fiber MTP cabling system is usually used in the following standards: 40GBASE-SR4, 40GBASE-PLRL4, and 40GBASE-PLR4. 40GBASE-SR4 is used for 40G transmission in short distances up to 150 meters over OM4 fibers. 40GBASE-PLRL4 and 40GBASE-PLR4 support transmission distance over single-mode fiber up to 1.4km and 10km separately. These standards use 40G parallel transceivers with 12-fiber MTP interfaces.

40G-SR4-QSFP+

Except 40G transceivers with 12-fiber MTP interfaces, there is a wide range of 12-fiber MTP connectivity components for transmission. These MTP cabling products cable be used in a lot of applications.

12-Fiber MTP Cabling Connectivity Components

12-Fiber MTP Trunk Cable: MTP trunk cable can be regarded as MTP to MTP fiber patch cable. MTP trunk cable is terminated with MTP connectors on both ends. The MTP connectors can be male (with guide pin on the contact interface) or female (without guide pin). As above mentioned, MTP cables can be divided into different types: Polarity A, Polarity B and Polarity C. A previous of my article “Understanding Polarity in MPO System” has introduced the polarity of MTP components. You can follow this article about the MTP polarity details.

The most commonly used MTP trunk cable is a single strand of cable, which can provide duplex 40G transmission at the same time. There are also MTP trunk cables which are composed by several strands of cables. Take the example of 12-fiber MTP trunk cables as shown in the following picture. On the left of this picture, there is a 12-fiber MTP trunk cable which is a single strand cable. On the right of this picture, there is a 72-fiber MTP trunk cable which is composed by 6 strands of 12-fiber MTP trunk cable.

12-fiber MTP trunk cable

12-Fiber MTP Harness Cable: MTP harness cable is a length of fanout cable with one end terminated with MTP connector and the other end terminated with several connectors like LC and SC. 12-fiber MTP harness cables also come in a variety of types according to fiber type, polarity type and connector types. The following picture shows a most commonly used MTP-4 duplex LC fiber cable.

MTP-8LC harness fiber cable

12-Fiber MTP Cassette: MTP cassette is like MTP harness cable which also provides the transferring between MTP interface and LC or SC interfaces. But MTP cassette can protect the fragile optical fibers inside the metal box, and has lower space requirements than MTP harness cable. The following picture shows a 12-fiber MTP-LC Cassette.

12-FIber MTP-LC Cassette

Typical 12-Fiber MTP Cabling Guide

The 12-Fiber MTP fiber optic products can be used in many situations not only for 40G fiber network. The following introduces several typical fiber cabling solutions using 12-fiber MTP products.

12-Fiber MTP Products in 10G to 10G Transmission

The following picture shows the wire guide for 10G to 10G connections using OM3 12-fiber MTP fiber cables and 12-fiber MTP-LC cassettes. A 10G link just uses two of the 12 fibers. On each end of this link, up to six 10GBASE-SR SFP+ modules can be connected to the fiber optic network, which means up to 60G can be transmitted by the following 12-fiber MTP system.

10G MTP fiber cabling

12-Fiber MTP Products in 40G to 40G Transmission

For 40G to 40G transmission, MTP trunk cable is usually being used. The following picture shows the connection of two brocade ICX 7750 switches over long transmission distance. Brocade compatible QSFP-PLR4-40G transceivers are being used on both ends of this 40G fiber link. 12-fiber MTP OS2 trunk cable is being used to connect the QSFP+ modules on each end.

40G-QSFP-PLR4 Cabling

    Items required in this 40G to 40G fiber optic link

  • QSFP-PLR4-40G QSFP+
  • OS2 12-Fiber MTP Trunk Cable

12-Fiber MTP products in 40G to 10G Transmission

Sometime the 40G device is still required to be connected with 10G devices. Here takes the example of connection between 40G QSFP+ port on Brocade 7750 and 10G SFP+ port on Brocade Fastlron FCX6245 over long transmission distances. To distribute the 40G signals into four 10G, Brocade compatible QSFP-PLR4-40G transceiver, and Brocade compatible 10G-LR SFP+ transceiver, 12-fiber MTP-LC cassette, 12-fiber MTP trunk cable and four LC-LC duplex single-mode fiber patch cables are used. The MTP cassette transmitting the MTP interface to the LC interfaces as shown in the following picture.

40G-PLR4 cabling

    Items required in this 40G to 10G fiber optic link

  • QSFP-PLR4-40G QSFP+
  • OS2 12-Fiber MTP Trunk Cable
  • OS2 12-Fiber MTP-LC Cassette
  • OS2 LC-LC Fiber Patch Cable
  • 10G-LR SFP+
Conclusion

12-fiber MTP cabling system is a cost-effective and space saving solution for both 10G and 40G transmission. As most of the MTP fiber products are factory pre-terminated, these products can provide fast installation and great network performance. FS.COM provides full range of MTP fiber optic products. You can visit FS.COM or contact sales@fs.com for more details about MTP fiber cabling.