Fiber Optic Blog

We know that fiber optic patch cables play a very important role in the connection between devices and equipment. When talking about fiber optic patch cables, we usually divide them into multimode fiber optic patch cables and singlemode fiber optic patch cables according to the modes of the cable. What is multimode fiber optic patch cable? How many types of multimode patch cables are there? And what is the difference between multimode and singlemode patch cables? What are the applications of multimode patch cables? This text will solve those questions one by one.

Introduction

Multi-mode fiber patch cables are described by the diameters of their core and cladding. There are two different core sizes of multi-mode fiber patch cords: 50 microns and 62.5 microns. Both 62.5 microns and 50 microns patch cable feature the same glass cladding diameter of 125 microns. Thus, a 62.5/125µm multi-mode fiber patch cable has a 62.5µm core and a 125µm diameter cladding; and a 50/125µm multi-mode fiber patch cable has a 50µm core and a 125µm diameter cladding. The larger core of multi-mode fiber patch cords gathers more light and allows more signals to be transmitted, as shown below. Transmission of many modes of light down a multi-mode fiber patch cable simultaneously causes signals to weaken over time and therefore travel short distance.

Types of Multimode Fiber Optic Patch Cable

Multimode fiber optic cables can be divided into OM1, OM2, OM3, and OM4 based on the types of multimode fiber. The letters “OM” stands for optical multimode. OM1 and OM2 belong to traditional multimode fiber patch cable, while OM3 and OM4 belong to the new generation fiber patch cable which provides sufficient bandwidth to support 10 Gigabit Ethernet up to 300 meters. The connector types include LC, FC, SC, ST, MU, E2000, MPO and so on. Different type of connector is available to different equipment and fiber optic cable.

By the materials of optic fiber cable jackets, multimode fiber patch cord can be divided into four different types, PVC, LSZH, plenum, and armored multimode patch cable. PVC is non-flame retardant, while the LSZH is flame retardant and low smoke zero halogen. Plenum is compartment or chamber to which one or more air ducts are connected and forms part of the air distribution system. Because plenum cables are routed through air circulation spaces, which contain very few fire barriers, they need to be coated in flame-retardant, low smoke materials. Armored fiber patch cable use rugged shell with aluminum armor and kevlar inside the jacket, and it is 10 times stronger than regular fiber patch cable.

Difference Between Singlemode and Multimode Patch Cables

Multimode and singlemode fiber optic patch cables are different mainly because they have different sizes of cores, which carry light to transmit data. Singlemode fiber optic patch cables have a core of 8 to 10 microns. Multimode fiber patch cable allows multiple beams of light passing through, while singlemode fiber cable allows a single beam of light passing through. As modal dispersion happens in multimode fiber cable, the transmission distance is relevantly nearer than singlemode fiber cables. Therefore, multimode fiber optic patch cable is generally used in relevantly recent regions network connections, while the singlemode fiber cable is often used in broader regions.

Applications of Multimode Fiber Optic Patch Cable

Multi-mode fiber patch cables are used to connect high speed and legacy networks like Gigabit Ethernet, Fast Ethernet and Ethernet. OM1 and OM2 cables are commonly used in premises applications supporting Ethernet rates of 10Mbps to 1Gbps, which are not suitable though for today’s higher-speed networks. OM3 and OM4 are best multimode options of today. For prevailing 10Gbps transmission speeds, OM3 is generally suitable for distance up to 300 meters, and OM4 is suitable for distance up to 550 meters.

Conclusion

Fiber optic patch cords are designed to interconnect or cross connect fiber networks within structured cabling systems. Typical fiber connector interfaces are SC, ST, and LC in either multimode or singlemode applications. Whether to choose a singlemode or multimode fiber patch cable, it all depends on applications that you need, transmission distance to be covered as well as the overall budget allowed.

Though fiber optic patch cord is a preferable option in a network, it also has the potential to be the weakest link in fiber network infrastructures. So it is very essential to follow correct procedures in administration of fiber patch cords to achieve optimum performance and reliability. Best practice in managing patch cords can be divided into four parts: planning, preparation, patching, and validation. This post will talk about fiber jumper management from these four aspects.

Planning

A good plan is half the success. Make sure you know the specifications and design of your fiber cabling. Fiber patch cords you choose must match the installed cabling. Do not mix them. Color-coding of connectors for different fiber standards make it easy to avoid confusion. First you need to find the best route between the ports to be connected to establish the correct cord length. This is usually the shortest route through horizontal and vertical cable guides that does not obstruct or interfere with other cords and connectors in the panel. By adding the horizontal and vertical distances, you get the required length. Avoid running cords through cable pathways that are already congested.

When selecting a cord to make a cross connection, avoid excessive slack and provide a neat appearance. Tight cords will pull on connectors and too much slack complicates cord management, making the panel more difficult to work on. Ensure that panels are fitted with correct cable management accessories. In general, a horizontal patch cord management guide is needed for every two rack units, depending on the type of optical patch panel or lightguide interconnect unit (LIU). At the optical patch panel or LIU, route patch cords equally toward both sides of the vertical cable management channels to prevent overloading one side.

Preparation

Before performing administration activities, preparation is critical. It can minimize disconnect time as much as possible. What preparation needs to be done? Locate the ports that must be connected or reconnected. Ensure technicians have clear information on what they need to do, including labeling information for the ports involved. Ensure cords are of the right type and quality, whether an MPO cable or a LC fiber cable or other connector types, and that they are clean and in good condition. Cleanliness is vital in fiber optic connections so special care is needed with connector ends on patch cords, panels and network equipment.

Patching

During the patching process, be careful not to use excessive force during the patching process, which can stress cords and connectors, reducing their performance. And exceeding the bend radius can result in significant additional loss and adverse impact on channel performance. Patching includes removing a patch cord and adding a patch cord. Steps in removing and adding cords:

Removing a patch cord

1. locate the existing circuit

2. unplug the patch cord at one end and cover the connector endface with a dust cap

3. cover the open port with a dust cover

4. gently lift the cord straight up, taking up slack until its movement is detected

5. follow the cord routing, gently removing it along its length from the cable pathways

6. find the other end and unplug it

7. fully remove the cord

Adding a patch cord

1. identify the location of the new circuit

2. plug one end of the patch cord into the fiber coupling

3. route the patch cord

4. locate the new connecting point

5. plug the other end of the patch cord into the fiber coupling

Validation

Patching must be right since mistakes can cause costly disruption and re-work. It is totally necessary and important to take some time to make a final visual check on connections. When patch panels are mounted in enclosures, ensure they are securely closed and, where necessary, locked, making sure that cord slack is not snagged or pinched by the doors. The final step is to update the documentation to the as-built configuration and close the work order associated with the completed change request.

Summary

To sum up, a good fiber cabling management depends on the four aspects above. A right plan, well preparation, careful patching and at last, a thorough validation, all these add up to a successful cable management. You need to make sure that every procedure is properly implemented.

While installing fiber optic cables, you will come across such questions. Should I choose to field terminate fiber optic cables or just turn to pre-terminated fiber optic cables? Which choice is better for the installation? Before jumping to a decision, you need to take a few things into consideration. In this article, we will discuss what cable construction type you need and understand why a pre-terminated fiber option is a better choice for you.

What May Pre-Terminated Fiber Cables Bring to You?

Pre-terminated cabling systems have been in use for a number of years. Nowadays they have been regarded as the “norm” for Data Center applications. There are reasons for it.

Time saving: Without doubt, pre-terminated fiber cables can help you save a lot of time. As the products are terminated in a factory environment and delivered to site, minimal engineering or assembly work is required on site. Pre-terminated solutions also save testing time. The pre-terminated solutions can be tested at the factory and transported to site, which minimises the occurrence of faulty connections.

Space Saving: Pre-terminated fiber cable is much higher in density. And, installers need space to store the components and work areas to make terminations. Using a pre-terminated solution can be space saving as the pre-terminated links are “made to measure” and they don’t need to be stored when delivered as needed and can be put to use immediately.

Pre-terminated cables or fiber optic patch cables assemblies eliminate time-consuming field-termination processes and provide a factory-tested and certified endface. But they also have disadvantages. Prepolished connectorized fibers can cost much more than epoxy-style field-polish connectors. And cable length needs to be precisely measured. If pre-terminated cables are too short, you will have to install a replacement; if they are too long, you will have to deal with installation issues associated with managing the extra cable length, which will also cause additional expense.

What May Field Termination Bring to You?

As you know, optical fiber, mainly made of glass, is very fragile and difficult to install. Termination of installing optical fiber cables has always been perceived as a difficult, expensive, and time-consuming process, whether the termination is done in the field or it is an in-house operation, which discourags a lot of installers. And now, with the development of new high speed systems, termination is becoming more and more difficult. For example, multi-mode fiber networks for 40Gbit/s and 100Gbit/s applications use parallel transmission with 8 or 20 fibers per link utilizing 12-fiber MTP/MPO connectors, making it harder to terminate than a single fiber connector. Instead, a pre-terminated MPO cable would be much easier. Why not choose to field terminate fiber optic cabling systems? Here are several troubles that a field termination may bring to you.

Polishing process: Polishing the fiber is one of the most critical step in the connectorization process. Polishing is the process of creating a smooth surface by rubbing it or using a chemical action, leaving a surface with a significant specular reflection. Polishing finalizes the connector endface and cleans the surface, which has a direct impact on such optical performance parameters as insertion loss, return loss, and bit-error-rate for overall network performance. Reliable polishing processes rely on proper training and a well-equipped termination toolkit. Many installers fear connectorizing optical fiber cable, mainly due to the delicate techniques of polishing.

Connector protection: Another problem is how to protect the connectors. We know that optical fiber connector is a high-precision device with tolerances on the order of microns, it is crucial that the fiber should not only be formed perfectly to align with a mating connector, but that it should be free of any dust or dirt. Failing to do so can cause high insertion loss and high reflection, and can contaminate the equipment to which the connectors and patch cords will be connected. In a field termination process, extra attention must be paid to the handling of the collectors. Bad environment may increase the possibility of a connector failure.

Cost: Besides, fiber termination involves a heavy investment into the proper tools and test equipment to make a proper fiber connection at the location. For example, you need a cable stripper to remove the tight buffer, a ruler and a marker to measure the length and mark on the fiber jacket, and some fiber optic cleaning fluid to clean the bare fiber, and so on. The most costly part of field termination kit is going to be your cleaver. Some only cleave multimode fibers and some do both multimode and singlemode fibers. So if you decide to field terminate fiber optic cables, you must prepare all those termination tools that you need, which is a big load for field termination.

How Do You Make A Choice?

Pre-terminated fiber cable is relatively a much easier way to install fiber cable. The connectors you specify are pre-terminated for you, and the fiber cable you specify is cut to the proper length that you need. When the installation is over, you can just plug and play fiber optic system. It is perfect for beginners and also convenient for professional fiber optic installers. Many cable and patchcord manufacturers offer a cable termination service. If you have a good cable plant layout design and can accurately calculate cable lengths between termination points, all you have to do is specify what kind and number of fibers, the fiber types and connector types and the cable length that you need. Then the manufacturer would supply a completed assembly, and the cable is terminated with connectors, fully tested and fitted with protective sleeving at each end. Pre-terminated fiber cable is an excellent choice.

Conclusion

Pre-terminated fiber cables do offer a number of advantages for a variety of different network installations for reasons of time saving and space saving. However, it doesn’t mean that you can get all the benefits offered by a pre-terminated solution. A large amount of planning needs to be carried out prior to installation. Attention to details in the site survey process is critical, or these benefits will be lost and additional cost incurred. A pre-terminated solution is a pre-planned solution. Only when you preplan it well can it work well.

In communication networks, many transmission lines need bidirectional transmission. This need leads to the development of Bidirectional (BiDi) transceivers, which can transmit and receive data to/from interconnected equipment through a single optical fiber. BiDi transceivers are fitted with wavelength division multiplexing (WDM) diplexers, which combine and separate data transmitted over a single fiber based on the wavelengths of the light. BiDi transceivers must be deployed in matched pairs, with their diplexers tuned to match the expected wavelength of the transmitter and receiver that they will be transmitting data from or to. In this post, a kind of BiDi transceiver, 1000BASE-BX SFP BiDi transceiver will be introduced.

Introduction

1000BASE-BX is a part of the Gigabit Ethernet standard related to transmission over fiber optic cable. 1000BASE-BX SFP modules are compliant with SFP Multi-Source Agreement (MSA) specification and SFF-8472, and conform to the IEEE 802.3ah 1000BASE-BX10 standard. 1000BASE-BX SFP modules include 1000BASE-BX-U SFP module and 1000BASE-BX-D SFP module. These two SFP modules must be used in pairs to permit a bidirectional Gigabit Ethernet connection using a single strand of single mode fiber (SMF) cable. These transceivers transmit and receive signals on one fiber strand using two wavelengths in each direction. These hot pluggable optical transceivers consist of two sections: the transmitter section uses 1490nm DFB laser/1310nm Fabry-Perot laser, and the receiver section uses 1310nm/1490nm receiver accordingly. The 1000BASE-BX-D SFP operates at wavelengths of 1490nm TX/1310nm RX, and the 1000BASE-BX-U SFP operates at wavelengths of 1310nm TX/1490nm RX. These transceivers use standard simplex LC connectors for fiber cable connection and provide a long transmission distance of up to 10 km.

Key Features

Data rate up to 1.25 Gbps

Hot-pluggable SFP footprint

1490 nm DFB Transmitter and 1310 nm PIN Receiver

1310 nm FP Transmitter and 1490 nm PIN Receiver

Transmission distance up to 10 km

Simplex LC connector

Low power dissipation

Digital diagnostic monitor interface is compliant with SFF-8472

Compliant with SFP MSA Specification

Compliant with IEEE 802.3z Gigabit Standard

RoHS compliance

1000BASE-BX-D SFP

1000BASE-BX-D SFP supports link length of up to 10km point to point on single mode fiber (1490nm-TX/1310nm-RX wavelength) at 1Gbps bidirectional. This optic uses an LC connector. The picture below show a Cisco GLC-BX-D compatible 1000BASE-BX-D SFP 1490nm-TX/1310nm-RX transceiver. The GLC-BX-D is a small form factor pluggable module for Gigabit Ethernet 1000BASE-BX and Fiber Channel communications. The GLC-BX-D transceiver operates at 1490Tx/1310Rx wavelength. It is compatible with the IEEE 802.3ah 1000BASE-BX10-D standards. A 1000BASE-BX-D device is always connected to a 1000BASE-BX-U device with a single strand of standard SMF.

1000BASE-BX-U SFP

1000BASE-BX-U SFP supports link length of up to 10km point to point on single mode fiber (1310nm-TX/1490nm-RX wavelength) at 1Gbps bidirectional. This optic uses an LC connector. The communication over a single strand of fiber is achieved by separating the transmission wavelength of the two devices. 1000BASE-BX-D transmits a 1490nm channel and receives a 1310nm signal, whereas 1000BASE-BX-U transmits at a 1310nm wavelength and receives a 1490nm signal. A wavelength-division multiplexing (WDM) splitter integrated into the SFP to split the 1310nm and 1490nm light paths. The GLC-BX-D and GLC-BX-U SFPs also support digital optical monitoring (DOM) functions according to the industry-standard SFF-8472 multisource agreement (MSA). This feature gives the end user the ability to monitor real-time parameters of the SFP, such as optical output power, optical input power, temperature and transceiver supply voltage. The picture below show a Cisco GLC-BX-U compatible 1000BASE-BX-U SFP 1310nm-TX/1490nm-RX transceiver.

Applications

Gigabit Ethernet

Fiber Channel Links

Switch to switch interface

Switched backplane applications

Pouter/Server Interface

Other optical transmission systems

Conclusion

New organizational applications, virtualization, and data center consolidation trends are pushing your server I/O requirements to meet higher needs than before. With new BiDi optical technology, SFP BiDi transceivers make it much easier for you to upgrade your networks.

40GBASE QSFP+ (quad small form factor pluggable) portfolio offers customers a wide variety of high-density and low-power 40 Gigabit Ethernet connectivity options for data center, high-performance computing networks, enterprise core and distribution layers, etc. And each kind of 40GBASE QSFP+ transceiver has its special applications. 40GBASE-LR4 QSFP+ transceiver is a common 40 Gigabit Ethernet connectivity option. Here is some basic information about 40GBASE-LR4 QSFP+ transceiver.

Introduction

40GBASE-LR4 QSFP+ module supports link lengths of up to 10 kilometers over a standard pair of G.652 single-mode fiber with duplex LC connectors. The 40 Gigabit Ethernet signal is carried over four wavelengths. Multiplexing and demultiplexing of the four wavelengths are managed within the device. The letter “L” stands for long, the “R” denotes the type of interface with 64B/66B encoding and the numeral 4 indicates numeral 4 indicates that the transmission is carried out over a ribbon fiber with four singlemode fibers in every direction. Each lane has a 10 Gbit/s data rate. 40GBASE-LR4 QSFP+ transceiver modules are compliant with the QSFP+ MSA and IEEE 802.3ba 40GBASE-LR4. The picture below shows a Mellanox MC2210511-LR4 compatible 40GBASE-LR4 QSFP+ transceiver.

Two Types of 40GBASE-LR4 QSFP+ Transceiver

There are mainly two of 40GBASE-LR4 QSFP+ transceivers, 40GBASE-LR4 CWDM (coarse wavelength division multiplexing) QSFP+ transceiver and 40GBASE-LR4 PSM (parallel single-mode fiber) QSFP+ transceiver. This part mainly talks about these two 40GBASE-LR4 QSFP+ transceiver types.

40GBASE-LR4 CWDM QSFP+ transceiver, such as QSFP-40GE-LR4, contains a duplex LC connector for the optical interface. It can support transmission distance of up to 10km. A 40GBASE-LR4 CWDM QSFP+ transceiver converts 4 inputs channels of 10G electrical data to 4 CWDM optical signals by a driven 4-wavelength distributed feedback (DFB) laser array, and multiplexes them into a single channel for 40G optical transmission. Then the receiver module accepts the 40G CWDM optical signals input, and demultiplexes it into 4 individual 10G channels with different wavelengths.

40GBASE-LR4 PSM QSFP+ transceiver is a parallel single-mode optical transceiver with an MTP/MPO fiber ribbon connector. It also offers 4 independent transmit and receive channels, each capable of 10G operation for an aggregate data rate of 40G. The transmitter module accepts electrical input signals compatible with common mode logic (CML) levels. All input data signals are differential and internally terminated. The receiver module converts parallel optical input signals via a photo detector array into parallel electrical output signals. The receiver module outputs electrical signals are also voltage compatible with CML levels.

Applications

QSFP-40GE-LR4 supports 40GBASE Ethernet rate only, whereas the QSFP-40G-LR4 supports OTU3 data rate in addition to 40GBASE Ethernet rate. 40GBASE-LR4 QSFP+ transceivers are most commonly deployed between data-center or IXP sites with single mode fiber.

fiber-mart.com offers customers a wide variety of 40GBASE-LR4 QSFP+ transceivers for your high-density and low-power 40 Gigabit Ethernet connectivity options, including 40GBASE-LR4 CWDM QSFP+ transceiver and 40GBASE-LR4 PSM QSFP+ transceiver, like Cisco QSFP-40GE-LR4 40GBASE-LR4 QSFP+ transceiver. fiber-mart.com also provides wide brand compatible 40G QSFP+ transceivers, such as Brocade QSFP+, Dell QSFP+, Juniper QSFP+, Mellanox QSFP+, and HP QSFP+. Each fiber optic transceiver provided by fiber-mart.com has been tested to ensure its compatibility and interoperability.

The number of network connections in data centers is on the rise. Data centers have to achieve ultra-high density in cabling. Multimode fiber optics is the medium of the future for satisfying the growing need for transmission speed and data volume over short distances. Parallel optics technology is what you get if you combine both trends—cabling density and the use of fiber optics. It is a suitable solution for high-performance data networks in data centers. This passage provides introductory information on parallel optics technology.

What Is Parallel Optics?

Parallel optics is a term used to represent both a type of optical communication and the devices on either end of the link that transmit and receive information. It differs from traditional fiber optic communication in that data is simultaneously transmitted and received over multiple optical fibers. In parallel optical communication, the devices on either end of the link contain multiple transmitters and receivers. For example, four transmitters on End A communicate with four receivers on End B, spreading a single stream of data over four optical fibers. With this configuration, a parallel optics transceiver can use four 2.5Gb/s transmitters to send one 10Gb/s signal from A to B.

Parallel optical devices are fundamentally different in construction from serial optical devices. Two complementary technologies have enabled the development and deployment of parallel optics devices: vertical cavity surface emission lasers (VCSELs) and the MPO connector. Parallel optic transmission technology spatially multiplexes or divides a high-data-rate signal among several fibers that are simultaneously transmitted and received. At the receiver, the signals are de-multiplexed to the original high-data-rate signal. MPO connectivity is used throughout the parallel optic link and interfaces into the transceiver module. An MPO connector and its connectivity method is showed in the picture below (Tx stands for transmit, Rx stands for receive).

Applications of Parallel Optics Technology

Parallel optic interfaces (POIs) are a fiber optic technology primarily targeted for short-reach multimode fiber systems (less than 300 meters) that operate at high data rates. Duplex fiber serial transmission with a directly modulated 850 nm VCSEL has been used to date for data rates up to 10G. Current and future protocols expected to use parallel optics include 40G and 100G Ethernet, InfiniBand and Fibre Channel speeds of 32G and higher. IEEE has already included physical layer specifications and management parameters for 40Gbps and 100Gbps operation over fiber optic cable. The uses of parallel optics technology continues to evolve and takes shape as higher-speed fiber optic transmission. Many cabling and network experts have pointed out that parallel optical communication supported with MPO technology is currently a way to equip an environment well prepared for the 40/100GbE transmission.

Why Choose Parallel Optics?

Parallel optical communication uses multiple paths to transmit a signal at a greater data rate than the individual electronics can support. Parallel transmission can either lower the cost of a given data rate (by using slower, less expensive optoelectronics) or enable data rates that are unattainable with traditional serial transmission. Moreover, POIs offer an economical solution that utilizes multimode fiber, which is optimized with VSCEL sources. This means that for speeds faster then 16G, parallel optics, is the most practical, cost-effective solution.

Parallel optics is one technology currently on the market for high data rates networking solutions. Fiberstore is a professional manufacturer and supplier, which offers a large amount of cables and transceivers for your parallel optics applications, such as QSFP+ transceiver and QSFP+ cable. Parallel optical transceivers used for 40GBASE-SR4 and 40GBASE-CSR4 have 10-Gbps electrical lanes that are mirrored in the optical outputs.