Which One to Choose, Singlemode QSFP+ or Multimode QSFP+?

Fiber optic transceivers also have singlemode and multimode types according to the fiber they work with. A simglemode QSFP+ transceiver works with singlemode fiber, and a multimode QSFP+ transceiver works with multimode fiber. What are thwy and what is the difference between them? How to choose? A cpmparison between these two kinds of QSFP+ transceivers will be given in this post.

Singlemode QSFP+ vs. Multimode QSFP+

Singlemode QSFP+: Singlemode fiber (SMF) has a tighter tolerance. The core of a singlemode fiber is smaller and the laser wavelength is narrower, which means that SMF has the capability for higher bandwidth and much longer transmission distances. Singlemode QSFP+ (SMF QSFP+) transceiver works mainly in 1310nm wavelength. It is mainly used for long distance transmission. There are several different types of singlemode QSFP+ transceivers. And different types can achieve different transmission distances, such as 500m, 1km, 2km, 10km or even 40km. For example, Cisco QSFP-40G-LR4 compatible 40GBASE-LR4 QSFP+ transceiver, as shown below, is a singlemode QSFP+ transceiver, uses duplex LC connector, and can transmit up to 10km. SMF QSFP+ transceivers usually use duplex LC connectors, and some types can use MPO/MTP connectors.

Multimode QSFP+: Multimode fiber (MMF) has a much bigger core and usually uses a longer wavelength of light. Optics used in MMF have a higher capability to gather light from the laser. In practical terms, this means that the optics can be cheaper. Common multimode QSFP+ (MMF QSFP+) transceiver works in 850nm wavelength and is mainly used for short distance transmission reaching 100m and 500m. For instance, Cisco QSFP-40G-SR4-S compatible 40GBASE-SR4 QSFP+ transceiver, as shown below, is a multimode QSFP+ transceiver, uses MTP/MPO connector, and can transmit up to 150m over OM4 MMF. Multimode QSFP+ transceiver is not able to transmit over long distance, but it can transport many kinds of optical signals. MMF QSFP+ transceivers usually use MPO/MTP connectors, but some SMF&MMF QSFP+ transceivers can also use duplex LC connectors.

Which One to Choose, Singlemode or Multimode?

SMF QSFP+ transceiver and MMF QSFP+ transceiver have different transmission distances and interface connectors, which are the two important factors you should consider when making make a decision. SMF QSFP+ transceivers are for long transmission distances and MMF QSFP+ transceivers are mainly for short transmission distances.

Notes for Using Singlemode QSFP+ and Multimode QSFP+

• Ensure that the QSFP+ transceivers in both ends of the fiber patch cord are of the same wavelength. A simple method is that the color of the modules must be consistent.
• Ensure the data accuracy. Short-wave QSFP+ modules use with multimode fibers (ie. aqua OM3 or OM4 fiber patch cord), while long-wave QSFP+ modules use with single-mode fiber (ie. yellow fiber patch cord).
• Do not over bend or wind fiber optic cables when using them, which will increase the attenuation of light in transmission.
• Use the dust plug to protect the optical bore when the QSFP+ transceiver is not in use.

Conclusion

When choosing a QSFP+ transceiver, first you need to figure out the transmission distance and wavelength you need. It is very crucial and can help you choose the right QSFP+ module. Besides, the cost of transceiver modules is also a very important factor for your consideration. An alternative is you can choose compatible modules without sacrificing quality and reliability. Fiberstore provides all kind of 100% compatible QSFP+ modules branded by many famous companies, such as Cisco, HP, Juniper, Brocade, and Finisar, etc.

MTP/MPO Cables — A Good Solution for Your High Density Applications

With rapidly growing bandwidth demands, data centers have to achieve ultra-high density in cabling to accommodate all connections. MTP/MPOtechnology with multi-fiber connectors offers an ideal solution for high-performance data networks in data centers. There are several MTP/MPO cable solutions, such as MTP/MPO trunk cables, MTP/MPO harness cables and MTP/MPO cassettes. And all these three kinds of MTP/MPO solutions have their own special applications and advantages. This article will give a brief introduction to them.

MTP/MPO Trunk Cable

An MTP/MPO trunk cable is terminated on both ends with MTP/MPO connectors (as shown in the following picture). MTP/MPO trunk cables are available with 12, 24, 48 or 72 fibers. These high count MTP/MPO assemblies are ideal for backbone and data center applications that require a high fiber count in a limited space. The plug and play solutions use micro core cable to maximize bend radius and minimize cable weight and size. MTP/MPO trunk cables have several advantages:

• High quality—MTP/MPO trunk cables are factory pre-terminated, tested and packaged along with the test reports. These reports serve as long-term documentation and quality control.
• Decreasing cable volume—MTP/MPO trunk cables have very small diameters, which decrease the cable volume and improve the air-conditioning conditions in data centers.
• Time saving—With the special plug and play design, MTP/MPO trunk cables can be incorporated and immediately plugged in. It greatly helps reduce the installation time. You don’t need to terminate them in the field, which can be a time- and energy-consuming project.

MTP/MPO Harness Cable

MTP/MPO harness cable (as shown in the following picture) is also called MTP/MPO fan-out cable or MTP/MPO breakout cable. MTP/MPO harness cable has a single MTP connector on one end and on the other end it breaks out into 6 or 12 connectors (LC, SC, ST, etc.). An MTP/MPO breakout cable is available in 4, 6, 8, or 12 fiber ribbon configurations with various length options like 10, 20, or 30 meters and other customized lengths. MTP/MPO fan-out assemblies provide connection to equipment or panels that are terminated with ST, SC, FDDI, or ESCON connectors and meet a variety of fiber cabling requirements. Such assemblies are pre-wired available for patch panels and wall enclosures. They are designed for high density applications with required high performance. Benefits of MTP/MPO harness cable include:

• Space saving—The active equipment and backbone cable is good for saving space.
• Easy deployment—Factory terminated system saves installation and network reconfiguration time.
• Reliability—High standard components are used in the manufacturing process to guarantee the product quality.

MTP/MPO Cassette

MTP/MPO cassettes are designed to reduce installation time and cost for an optical network infrastructure in the premises environment. MTP/MPO cassette modules provide secure transition between MTP/MPO and LC or SC discrete connectors. They are used to interconnect MTP/MPO backbones with LC or SC patching. The modular system allows for rapid deployment of high density data center infrastructure as well as improved troubleshooting and reconfiguration during moves, adds and changes. Advantages of MTP/MPO cassettes are:

• Optimized performance—Low insertion losses and power penalties in tight power budget, high-speed network environments.
• High density—12 or 24 fiber cassettes can be mounted in 1U scaling up to 72 or in 3U scaling up to 336 discrete LC connectors.
• MTP/MPO interface—MTP/MPO components feature superior optical and mechanical properties.

Applications of MTP/MPO Cable

MTP/MPO cables are a good choice for a wide variety of applications. They can be used for backbones, disaster recovery, building fiber optic distribution, quick setup of new wiring hubs, warehouses, direct termination of ribbon cables, repair of plug and play universal system solutions, and parallel optical interconnects between servers.

MTP/MPO system is a good solution for data center applications. They can enable thousands of connections. Fiberstore offers a wide range of fiber optic patch cables, including all kinds of MTP/MPO cables, like MTP/MPO trunk cables, MTP/MPO harness cables and MTP/MPO cassettes. All those MTP/MPO cables are pre-terminated and tested to make sure high performance.

SFP+ Direct Attach Cable Overview

More bandwidth is needed to support the use of server virtualization. The amount and type of devices residing on the network has also dramatically increased the amount of data that needs to be transmitted to and from storage area networks (SANs). SFP+ direct attach cable (DAC), which provides a lower-power means for operation on short fiber optic links or short copper connections, has been a preferable solution to accommodate the ever-growing number of operating systems and applications and the significantly increased data transmission between the servers and switches. This post will give a brief introduction to SFP+ direct attach cable.

What Is SFP+ Direct Attach Cable?

First, we need to know what SFP+ direct attach cable is. It is a fixed assembly that is purchased at a given length, with SFP+ connector modules permanently attached to each end of the cable. SFP+ direct attach cable uses an enhanced SFP+ connector to transmit and receive 10Gbps data through one paired transmitters and receivers over a thin twinax cable or a fiber optic cable. It provides high performance in 10 Gigabit Ethernet network applications. 10G SFP+ direct attach cable is designed to use the same port as an optical transceiver, but compared with optical transceivers, the connector modules attached to the cable leave out the expensive optical lasers and other electronic components, thus achieving significant cost savings and power savings in short reach applications.

Advantages of SFP+ Direct Attach Cable

SFP+ direct attach cable is a low cost, low power consumption and low latency solution that is ideal for high-density, in-rack 10Gbps connections between servers and switches. It provides better cable management for high-density deployments and enhanced electrical characteristics for the most reliable signal transmission. Here are several outstanding advantages of SFP+ direct attach cables.

• MSA compliant—fully conform to the SFP+ MSA specifications
• High speed—support 10 Gbps data rates with backwards compatibility to 1 Gbps
• Reliability—RoHS compliant with excellent EMI performance and high reliability
• Scalability and flexibility—provide enhanced scalability and flexibility, and higher density for today's data centers and storage area networks
• Space saving—offer the smallest 10 gigabit form factor and a small overall cable diameter for higher density and optimized rack space in 10G Ethernet uplinks and Fibre Channel
• Cost saving—cost up to three times less than fiber optic solutions, while offering lower latency and consuming up to 50% less power per port than current copper twisted-pair cabling systems

Types of SFP+ Direct Attach Cable

Generally speaking, SFP+ direct attach cable can be divided into SFP+ direct attach copper cables and SFP+ active optical cables (AOCs). This part will discuss these two kinds of SFP+ direct attach cables.

There are two types of SFP+ direct attach copper cables, SFP+ active copper cable (ACC) and SFP+ passive copper cable (PCC). SFP+ passive copper cable (PCC), or passive SFP+ DAC, is fully compliant to the SFF-8431 SFP+ MSA. It has no signal amplification in the cable assembly. When it is utilized, electronic dispersion compensation (EDC) is typically used on the host board designs. EDC allows for an extended length of passive cable assemblies. They deliver high-speed connectivity between active equipment with SFP+ ports. The copper cable trunks are made to order, reducing installation time and maximizing flexibility. The low power consumption assists in making the passive copper cable assembly an economic solution for within rack or rack to rack applications. SFP+ active copper cable (ACC) has signal amplification and equalization in the cable assembly. SFP+ ACC assemblies are typically used in host systems that do not employ EDC. They also incorporate Rx LOS and Tx Disable features. As with passive cables, the industry standard EEPROM signature enables the host system to differentiate between an active copper cable and a fiber optic transceiver. The picture below shows an HP JG081C compatible 10G SFP+ passive direct attach copper cable.

SFP+ active optical cable is composed of SFP+ optical transceivers in both ends and fiber optic cable in between. This integrated optical module solution removes the complicated optical fiber interface and brings friendly electrical-to-electrical interface to users. SFP+ AOC accepts the same electrical inputs as a traditional copper cable. It uses optical fiber and electrical-optical conversion on the cable ends to improve speed and data transmission distance of the cable while not sacrificing compatibility with standard electrical interfaces. SFP+ AOC is designed to meet the requirements of high speed, high density and low power consumption for applications in today’s data centers via optical fiber wire. It has been a preferable interconnect solution for SFP+ applications. SFP+ AOC is compliant to industrial standard SFP MSA and provides high performance SFP+ interfaces, supporting 10Gb/s bi-directional operation. The image below shows a Cisco SFP-10G-AOC10M compatible 10G SFP+ active optical cable.

Conclusion

SFP+ direct attach cable provides a cost-effective and low power consumption solution for high-density 10 Gigabit connections. These three types of 10G SFP+ direct attach cable assemblies, 10G SFP+ passive copper cable (PCC), 10G SFP+ active copper cable (ACC), and 10G SFP+ active optical cable (AOC) are of their special applications. SFP+ direct attach cable has a lot of advantages. It now has been a very popular choice in the market.

Why Choose Push-Pull Tab Patch Cords?

Nowadays, with more and more data centers upgrading to 40G and even 100G, high density seems to have been the trend in the optical communication industry. Switches are able to provide more ports and higher data rates due to the shrinking of port size and advancement of technology. In order to fit these ports to achieve photoelectric conversion with higher data rate, fiber optic transceivers also shrink largely in both sizes and interfaces. For example, 40GBASE QSFP+ transceiver, supporting transmission data rate of 40G, has a small size and small MPO or LC interfaces. However, high density also brings a new problem.

Why Push-pull Tab Patch Cable Comes out?

It is inevitable that fiber optic connectors need to be plugged into or pulled out from switches during the cabling process and daily maintenance. For a high density cabling, it becomes much more difficult to get access to each patch cable and connector with your fingers. And it is almost impossible to unplug those connectors on a high density patch panel, especially when they are right in the middle of the patch panel. And also, for fiber patch cords with connectors like LC connector that are locked into the interfaces, it would be even more difficult, because first you have to unlock the connector and then pull it out from the port. High density cabling and maintenance seems to be difficult and time-consuming. To solve these kinds of situations, a special tool comes out, which is push-pull patch cord, or push-pull tab patch cable. Push-pull tab patch cable offers you a simple and easy solution for your high density cable management. And the following text will explain what it is and why you should choose it.

What Is Push-pull Tab Patch Cable?

Push-pull tab patch cable is a new patch cord with a special "pull" tab design which can help to solve the problem of finger access in high density cabling. It has the same components and internal structure as traditional patch cords, except a tab attached to the connector used to push in and pull out the whole connector. But this little change can make a big difference. This small push-pull tab looks simple but it is functional and of great importance to high density cabling in 40/100G migration. There are mainly two kinds of push-pull tab patch cables, for high density cabling for 40G/100G usually employs MPO and LC connectors.

Push-pull Tab LC Patch Cable: The main body of the LC connector is of standard size. The push-pull tab looks simple but it is linked to the latch of the LC connector. When the tab is pulled the latch will be unlocked easily and the LC connector can be easily pulled out from the patch panel. It has been proved that pull tab LC patch cord can increase cabling density greatly.

Push-pull Tab MPO Patch Cable: The tab in an MPO connector can greatly simplify the use of MPO connectivity when manual access to the release slider and rear portion of the connector is restricted. With this tab design, easy insertion and extraction of MPO patch cords can be achieved.

What Benifits Do Push-pull Tab Patch Cables Have?

Why choose push-pull tab patch cables? They are chosen for reasons. The benefits of push-pull tab patch cords are not limited to the easy access of the optical connectors. There are other benefits that you can get from them.

• Higher flexibility and adjustability: Push-pull patch cords are available in various specifications, so they can connect devices from 10Gb/s to 100Gbp/s or even more.
• Reliability: Push-pull tab patch cords provide safe and easy push and pull of specific connectors without affecting other connectors around it.
• Space-saving: With push-pull tab patch cords, spare space for cabling is reduced, which can increase the density of cabling further more.
• Economical: High density and ease of installation provide a low initial investment cost. And the benefits above provide a high return on investment.

Conclusion

Cabling with push-pull tab patch cords becomes much easier. All you need is just your hand and no external tools are required. Push-pull tabs can offer exceptional finger access even in a very highly dense environment. Push-pull patch cords can be inserted and removed just by pulling or pushing the connector. And these cables are available with OM3, OM4 and single-mode optical cable types. If you are looking for a connection solution for your high density devices, push-pull tab patch cords, with high durability and flexibility, can be a good a choice.

How to Choose a QSFP+ transceiver?

40G Ethernet standard now is already a popular choice for the rapid growth of global regional and local fiber communication network. For 40G network applications, fiber optic transceivers of two different package forms are commonly used, which are QSFP+ transceiver (quad small form-factor pluggable plus transceiver) and CFP transceiver (C form-factor pluggable transceiver). QSFP+transceiver is more popular in 40G application. Today we are going to discuss how to choose the 40GBASE QSFP+ transceiver. When choosing, there are several factors that you need to take into cinsideration, such as the media system, the connector type, transmission distance, wavelength, etc. The following text will talk about these factors one by one.

Fiber Type

First, choose the right QSFP+ transceiver according to the transport media, namely the fiber type. According to the IEEE 802.3ba 40G Ethernet standard, there are three types of transceivers used respectively in three types of transport media: single mode fiber (SMF), multimode fiber (MMF) and copper.

• SMF: 40GBASE-LR4 QSFP+ transceiver reaches 40 Gb/s Ethernet over four wavelengths carried by a singlemode fiber optic cable.
• MMF: 40GBASE-SR4 QSFP+ transceiver reaches 40 Gb/s Ethernet over four short-range multimode fiber optic cables.
• Copper: 40GBASE-CR4 QSFP+ transceiver reaches 40 Gb/s Ethernet over four short-range twinaxial copper cables bundled as a single cable over a standard pair of G.652 single-mode fiber.

Interface Type

Choose the right transceivers which are compliant with the proper connectors. The connectors widely-used mainly have following types: duplex LC connector and MPO connector (or MTP connector, a high-performance MPO connector). For instance, Cisco QSFP-40G-LR4 40GBASE-LR4 QSFP+ transceiver is compliant with the duplex LC connector, while Cisco QSFP-40G-SR4-S 40GBASE-SR4 QSFP+ transceiver and HP JG709A 40GBASE-CSR4 QSFP+ transceiver are compliant with the MPO connector. The picture belows shows duplex LC connector and MPO (MTP) connector.

Wavelength

The wavelength that QSFP+ transceivers operate on is another important factor in choosing the proper QSFP+ transceiver. For instance, QSFP-40G-LX4 QSFP+ transceiver converts 4 inputs channels (1271nm, 1291nm,1311nm, 1331nm) of 10Gb/s electrical data to 4 CWDM optical signals, and multiplexes them into a single channel for 40Gb/s optical transmission. While some other QSFP+ transceivers like QSFP-40GBD-SR QSFP+ transceiver consists of two 20-Gbps transmit and receive channels in the 832-918 nm wavelength range.

Transmission Distance

When choosing the most appropriate QSFP+ transceiver, you also need to consider the transmission distance and the reach requirements you need in reality. The most common types of QSFP+ transceiver divided by its transmission distance can reach up to 100m, 150m, 300m, 400m, 1km, 2km, 10km, 40km, etc. For example, 40GBASE-LR4 QSFP+ transceiver can reach up to 10km, suitable for long reach transmission; 40GBASE-LX4 QSFP+ transceiver is designed to supports link lengths of 100m and 150m respectively on laser-optimized OM3 and OM4 multimode fiber cables. And some others, like 40GBASE-ER4 QSFP+ transceiver which supports link lengths of up to 40km on single-mode fiber cable is designed to use in long distance transmission.

Cost

The total cost on QSFP+ transceivers is a large sum of money. Cost is one aspect that should be considered in 40G QSFP+ transceiver selection. To a limit buget, you have to figure out the best choice. Third party transceivers that are compatible with a variety types of switches can be found in today's market. They have the same performances that the original brand transceivers have, but cost less money. Selecting compatible QSFP+ transceivers has become the choice of many data centers, and it is necessary to select them from a company that assures 100% compatibility and interoperability.

Summary

Before choosing a QSFP+ transceiver, you must first find out what kind of QSFP+ transceiver you need. Whether you need singlemode fiber QSFP+ transceiver or multimode fiber QSFP+ transceiver, duplex LC connector or MPO connector, or you need it to transmit 100m or 10km, you should consider all the above-mentioned factors comprehensively. Only by doing so can you make the best selection for your network.

Is Pre-Terminated Fiber Cable A Better Choice?

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.