QSFP+ Optics for High-Density 40GE Connectivity

With the development of the SFF-8436 Multi Source Agreement, many vendor are now offering a variety of IEEE- and MSA-compliant Quad Small Form-Factor Pluggable Plus (QSFP+) devices for fiber networks. And there are basic three 40G QSFP+ optics for this standard: 40G LR4 QSFP+ transceiver, 40G SR4 QSFP+ transceiver and 40G LR4 parallel single mode (PSM) transceiver. This article will take a close look at these 40G QSFP+ optics for high-density 40 GE connectivity.

40G LR4 QSFP+ Transceiver

Conforming to the 802.3ba (40GBASE-LR4) standard, the 40G LR4 QSFP+ transceiver together with the LC connector can support an optical link length up to 10 kilometers over single mode fiber. For example, the following Juniper JNP-QSFP-40G-LR4 compatible 40GBASE-LR4 QSFP+ transceiver offers 4 independent transmit and receive channels, supporting link distance of 10 km over single mode fiber. In the process of transmitting, this kind of transceiver has to introduce MUX/DEMUX to multiplex/de-multiplex optical signals.

The working principle of this kind of QSFP+ transceiver is : in the transmit side, four 10 Gbp/s serial data streams are passed to laser drivers. The laser drivers control directly modulated lasers (DMLs) with wavelengths. the output of the four DMLs are optically multiplexed to a single-mode fiber through an industry-standard LC connector. In the receive side, the four 10 Gbp/s optical data streams are optically de-multiplexed by the integrated optical demultiplexer; then, each data steam is recovered by a PIN photodetector/transimpedance amplifier and passed to an output driver.

40G SR4 QSFP+ Transceiver

The 40G SR4 QSFP+ transceiver, conforming to the 802.3ba (40GBASE-SR4) standard, provides a 40G optical connection using MPO/MTP fiber ribbon connectors. Unlike the 40G LR4 QSFP+ transceiver, this kind of transceiver are used together with multi-mode fiber, supporting with a link length up to 100 meters on OM3 cable and 150 meters on OM4 cable.

The operating principle of the 40G SR4 QSFP+ Transceiver is : the transmitter convertsparallel electrical input signals into parallel optical signals through the use of a laser array. Then the parallel optical signals are transmitted parallelly through the multi-mode fiber ribbon. Reversely, the receiver converts parallel optical input signals via a photo detector array into parallel electrical output signals.

40G LR4 Parallel Single Mode (PSM) Transceiver

40G PSM transceivers are used to provide support for up to four 10Gb Ethernet connections on a QSFP+ port over single mode fiber. These transceivers support distance of up to 10 kilometers over single mode fiber using an 8 parallel fiber MPO interface. Each fiber pair can be broken out to a 10Gb Ethernet connection, compatible with up to four 10GBASE-LR interfaces. The MPO to 4 x LC single mode fiber patch cord can be used to breakout the 4 fiber pair of the MPO parallel connector to 4 separate fiber pairs.

Summary

To sum up, 40G SR4 QSFP+ transceivers are suitable for short-distance transmissions. So they are often used in data centers to interconnect two Ethernet switches with 12 lane ribbon OM3/OM4 cables. while 40G LR4 QSFP+ transceivers and 40G LR4 PSM transceivers are often used in long-distance transmission applications. Fiberstore offers a wide range of 40G QSFP+ transceivers, like 40GBASE-SR4, 40GBASE-LR4, 40GBASE-CR4 QSFP+ transceivers, etc. Besides, we also provide 40G direct attach cables, such as Juniper QFX-QSFP-DAC-1M, Cisco QSFP-4X10G-AOC3M and so on.

Reference:http://www.fiber-optic-transceiver-module.com/basic-40g-qsfp-optics-for-40g-transmission.html

When Is It Best To Use Multimode Fiber Optic Cable?

Fiber optic cables are the medium of choice in telecommunications infrastructure, enabling the transmission of high-speed voice, video, and data traffic in enterprise and service provider networks. Generally speaking, there are two major kinds of fiber-optic cabling: single-mode and multi-mode.

While it's not impossible to get the two types to interact with the right transceivers and intermediate hardware, there's significant signal loss involved in the transition and, therefore, much higher power requirements to re-boost it. It's best to simply lay the kind of fiber that best meets your needs.

What Makes Multi-Mode Fiber Different

The significant difference in multi-mode is the size of its "core," the actual glass wire which holds/transmits optical signals. While single-mode uses a very thin core, which isolates the laser to a single beam, multi-mode allows it to reflect back and forth within the core. The following factors make multi-mode fiber superior to single-mode fiber in some certain aspects.

1. Specifically designed for use with “cheaper” light sources.

• The wide core lets you use incoherent LED light sources.
• Or cheaper, less precisely aimed lasers (such as VCSELs).
• And reduces tolerance requirements for alignment of connectors.

2. But this comes at the expense of long-distance reach.

• The wide core allows multiple modes of light to propagate.
• This causes “modal distortion”, which severely limits distance.
• Typically limited to 20-500 meters, depending on the signal type.

3. Augmented with “laser optimized” (OM3) MMF

• Uses aqua colored cables, rather than the traditional orange.
• Designed to achieve 10Gbps at 300 meters with VCSEL lasers. For example, both Finisar FTLX8571D3BCV and NETGEAR AXM761 SFP+ transceiver can reach distance of 300m over OM3 multi-mode fiber at the max data rate of 10 Gbps.    

Typical Uses For Multi-Mode Fiber

1 - A Fiber Backbone
Broadly, the most common application for multi-mode is to create a backbone for a company's network. If you're looking at 802.11ac or newer WiFi access points, a multi-mode fiber backbone is virtually required to get top speeds out of your access points.

2 - High Speed Local Deployments
Some businesses, especially those dealing in very large data sets, are starting to simply roll out multi-mode throughout their office. If your employees are regularly sending gigabyte-sized files around, this is currently one of the best options for boosting their transmission speeds.

3 - "Fiber To The Telecom Enclosure" (FTTE)
As a compromise between the two above options, some companies split it down the middle. The fiber connection continues past their server, and goes to a "Telecommunications Enclosure" (TE) which is in a central location, near to the employees connected to it.

It's an affordable way to deliver fiber, almost all the way to the desktop, without the higher expenses of a full wiring job. The main drawback is that your TE is nearly as vulnerable as your server room in terms of security, and would have to be tightly protected from intrusion.

Summary

When it is best to use multi-mode fiber optic cable is determined by many factors, like the distances, costs, associated transceivers, etc. It must be selected according to specific applications and needs. As one of the main fiber optical manufacturers in China, Fiberstore offer various types of fiber optic cables including single-mode, multimode as well as plenum cable, PVC/LSZ cable and so on to meet your specific applications and needs. With the higher bandwidths, flexibility, and security, all these fiber optic cables offer a promising solution to current networking challenges.

Reference:http://info.hummingbirdnetworks.com/blog/when-is-it-best-to-use-multimode-fiber-optic-cable

FAQ on Fiberstore 40G Cabling and Transceivers

With an increasing demand for more bandwidths, faster data rates and higher performance in telecommunication networks, the business case for 40 Gigabit Ethernet is becoming inescapably compelling. However, many users may feel confused when using 40G cables and optical transceivers. This article will solve the most frequently asked questions on Fiberstore’s 40G cabling and transceivers.

Q1: What 40G cables and transceivers are available from Fiberstore?
Fiberstore supplies a full range of both copper cables and optical transceivers for 40GbE, compliant to the IEEE standards. For copper both QSFP+ to QSFP+ (40G to 40G) and QSFP+ to SFP+ (40G to 4x10G) cables enable short reach options. For longer distances, Fiberstore offers a wide range of optical transceivers for various fiber types and reach requirements.

Q2: What does the IEEE 40GBASE-X standard describe?
The IEEE 40GBASE-X standard describes the following:

• 40GBASE-SR4
  It reaches 40-Gbps Ethernet over four short-range multimode fiber optic cables and supports link lengths of 100m and 150m respectively on laser-optimized OM3 and OM4 multimode fiber cables. In this process, the multimode fiber uses parallel-optics transmission instead of serial transmission due to the 850nm vertical-cavity surface-emitting laser (VCSEL) modulation limits. For example, Mellanox MC2210411-SR4 compatible 40GBASE-SR4 QSFP+ transceiver from Fiberstore supports link length of 100m over multimode fiber cable.
• 40GBASE-LR4
  It reaches 40-Gbps Ethernet over four wavelengths carried by a single long-distance singlemode fiber optic cable and supports link lengths of up to 10 km over single-mode fiber with duplex LC connectors. It operates at a wavelength of 1310 nm. The 40 Gigabit Ethernet signal is carried over four wavelengths with 10G on each wave.
• 40GBASE-CR4
  It is a direct attach cable segment with the QSFP+ modules attached to each end of the cable. It reaches 40-Gbps Ethernet over four short-range twinaxial copper cables bundled as a single cable and supports link lengths of up to 10 km over a standard pair of G.652 single-mode fiber with duplex LC connectors.

Q3: Can the 40G-LR4 transceiver be split into 4x10G connections?
No, 40G-LR4 cannot be split into 4x10G. The 40GBASE-LR4 uses 4 lambdas (or wavelengths) on a pair of single mode fibers, and does not lend itself to “splitting” into 4 pairs without substantial complexity to split out the wavelengths. The unique characteristic of 40GBASE-SR4 is that it uses parallel (ribbon) fiber, which allows the creation of 4 fiber pairs. As an alternative single mode parallel 40G optics are available (40G-PLRL4 and 40G-PLR4) that do allow for splitting into 4x10G (single mode).

Q4: How does the QSFP+ to SFP+ fiber convertor allow 4x 10G?
The IEEE 40G-SR4 standard specified a parallel technology, with 4 lanes in each direction. The purpose of this was to allow for easier development of 40G, re-using 10G components. As a side result the 40G multi-mode transceivers can also support 4x10G modes. A fiber that connects from one 40G port to four 10G ports provides a physical path to allow the source “40G” port running in 4x10G mode to be connected to 4 unique 10G destinations. As the fiber is a passive medium it has no concept of the 40G or 10G signals.

Fiberstore provides various types of 40G cables and transceivers including single-mode and multi-mode with different channels and wavelengths. All these transceivers are compatible with famous brands, like Brocade QSFP+, HP QSFP+, Juniper QSFP+, etc. They can also be customized to meet your special requirements.

High-density Cabling With MTP/MPO Connectors

With the expected increase in use of 40 Gbps and 100 Gbps, there is an increasing demand for higher and higher density fiber cabling solutions. Existing and emerging network technologies are driving the need for increased data rates and fiber usage in the data center. High-density cabling with MTP/MPO connectors is essential to address these trends to provide an easy migration from duplex fiber serial transmission to 12- and 24-fiber parallel optics transmission.

What Is MTP / MPO Connector

The MPO connector is a multi-fiber connector defined according to IEC 61754-7 and TIA/EIA 604-5 that can accommodate up to 72 fibers in the tiniest of spaces, comparable to an RJ45 connector. MPO connectors are most commonly used for 12 or 24 fibers. To achieve lower tolerances and better attenuation values, the US Conec developed the MTP connector which has better optical and mechanical quality than the MPO. MTP/MPO connectors provide the following benefits:

• A single 12 fiber connector at one end connects to multiple duplex connectors at the other end such as LC or SC
• Linking cables can be pre-connected to modules which are then placed in patch panels above the equipment
• Modules can be replaced and upgraded if required
• Scalable and adaptive to technology changes
• Module can be replaced with a fan-out and adapter plate if required

MTP / MPO Cable Assemblies

Since field termination is becoming widely available, MTP/MPO technology and MTP/MPO cable assemblies listed below are becoming more and more popular.

MTP / MPO Trunk Cable

MTP/MPO trunk cables are terminated with the MTP/MPO connectors. Trunk cables are available with 12, 24, 48 and 72 fibers. MTP/MPO trunk cables are designed for data center applications. The plug and play solutions uses micro core cable to maximize bend radius and minimize cable weight and size.

MTP / MPO Cable Harness

MTP / MPO cable harness is also called MTP / MPO breakout cable or MTP / MPO fan-out cable. This cable has a single MTP connector on one end That breaks out into 6 or 12 connectors (LC, SC, ST, etc.). The MTP / MPO harness assembly has Become a popular method for connections into high-port-count network switches.

Push-Pull MTP / MPO Patch Cable

A push and pull cable has the same components and internal-structure as the traditional patch cords, except a tab attached to the connector used for pushing or pulling the whole connector. This small push-pull tab looks simple but it is functional for high density cabling in 40/100G migration. The Push-Pull MTP/MPO patch cable for highest density allows high-density MTP presentation underneath SAN switches or proximate to super computers. It also provides access to 192 MTP connections in 2U of height space.  

The Trend for High-density Cabling

MTP/MPO style pre-terminated cables offer a market-leading low loss, fast and efficient connection system particularly suited to the data center and storage area network environment. The following factors lead to the trend for high-density cabling:

• Reduced cable size and increased air-flow to equipment
• High Density blade servers with hundreds of ports
• Virtualisation and cloud-computing
• High real-estate costs for rack space
• Reduced installation times
• Structured cabling approach (zone approach)
• 40G and 100G parallel optics

Fiberstore offers you a wide selection of MTP/MPO style pre-terminated cables including MTP/MPO trunk cable, MTP/MPO harness cable, Push-Pull MTP/MPO patch cable. Besides, we also provide Push-Pull tab LC patch cord and other related fiber cables. All these cables are with high flexibility and reliability. They can be customized according to your special requirements.  

Installing and Removing a QSFP+ Transceiver

Overview

The 40-Gigabit QSFP+ transceiver module is a hot-swappable, parallel fiber-optical module with four independent optical transmit and receive channels. These channels can terminate in another 40-Gigabit QSFP+ transceiver, or the channels can be broken out to four separate 10-Gigabit SFP+ transceivers. The QSFP+ transceiver module connects the electrical circuitry of the system with either a copper or an optical external network. The transceiver is used primarily in short reach applications in switches, routers, and data center equipment where it provides higher density than SFP+ modules.

Installing a QSFP+ Transceiver

The QSFP+ transceiver module can have either a bail-clasp latch or a pull-tab latch. Installation procedures for both types of latches are provided.

To install an QSFP+ transceiver module, follow these steps:
Step 1 Attach an ESD wrist strap to yourself and a properly grounded point on the chassis or the rack.
Step 2 Remove the QSFP+ transceiver module from its protective packaging.
Step 3 Check the label on the QSFP+ transceiver module body to verify that you have the correct model for your network.
Step 4 For optical QSFP+ transceivers, remove the optical bore dust plug and set it aside.
Step 5 For transceivers equipped with a bail-clasp latch:
a. Keep the bail-clasp aligned in a vertical position.
b. Align the QSFP+ transceiver in front of the module's transceiver socket opening and carefully slide the QSFP+ transceiver into the socket until the transceiver makes contact with the socket electrical connector. (See Figure1)

Step 6 For QSFP+ transceivers equipped with a pull-tab:
a. Hold the transceiver so that the identifier label is on the top.
b. Align the QSFP+ transceiver in front of the module's transceiver socket opening and carefully slide the QSFP+ transceiver into the socket until the transceiver makes contact with the socket electrical connector.
Step 7 Press firmly on the front of the QSFP+ transceiver with your thumb to fully seat the transceiver in the module's transceiver socket. (See Figure2)

Step 8 For optical QSFP+ modules, reinstall the dust plug into the QSFP+ transceivers optical bore until you are ready to attach the network interface cable. Do not remove the dust plug until you are ready to attach the network interface cable.

Removing a QSFP+ Transceiver

To remove a QSFP+ transceiver, follow these steps:
Step 1 For optical QSFP+ transceivers, disconnect the network interface cable from the QSFP+ transceiver connector.
Step 2 For QSFP+ transceivers equipped with a bail-clasp latch (See Figure3, top view):
a. Pivot the bail-clasp down to the horizontal position.
b. Immediately install the dust plug into the transceivers optical bore.
c. Grasp the sides of the QSFP+ transceiver and slide it out of the module socket.

Step 3 For QSFP+ transceivers equipped with a pull tab latch (See Figure3, bottom view):
a. Immediately install the dust plug into the transceiver's optical bore.
b. Grasp the tab and gently pull to release the transceiver from the socket.
c. Slide the transceiver out of the socket.
Step 4 Place the QSFP+ transceiver into an antistatic bag.

Conclusion

As 40 GbE are widely deployed, 40G transceiver optics are ubiquitous. A good practice and correct installation are very important for 40G network system, not only to protect the 40G transceiver optics and device from damage, but also to ensure a stable performance of the system. Fiberstore offers a wide range of 40G transceiver modules, such as QSFP-40G-LR4-S, QSFP-40G-SR4-S, QSFP-40G-ER4, etc. All these transceivers are tested in the original-brand switches to guarantee the high compatibility with major brands. For more information or quotation, please contact us via sales@fs.com.

Detailed Breakdown of MPO Connectors and 40G QSFP+ Transceivers

As the speed and transfer rates of computer hardware continue to grow alongside demand for ever-more data, new cabling becomes a necessity to keep up. Backbones for 40G on multimode fiber generally use MPO connectors which work with QSFP+ transceivers to allow four simultaneous 10G or better connections. An upgrade to QSFP+ can mean a significant reduction in overall cabling, which brings better reliability and cost-effectiveness.

MPO can work at higher speeds as well, able to bundle hundreds of individual fiber lines at once into a single terminator. As this is a relatively new standard, MPO connectors are not well-understood by many people. However, they're necessary to deliver the speeds promised by today's top-line backbones.

Things You Need To Know About MPO Connectors

1. What Is MPO

MPO is short for the industry acronym—"multi-fiber push on". The MPO connector is a multi-fiber connector which is most commonly defined by two documents: IEC-61754-7 and EIA/TIA-604-5. Here is a MPO connector with parallel optics transceiver and pinouts for 40G and 100G. Generally, the backbone cable that is permanently installed will end in connectors with pins inside mating adapters, effectively creating a "socket" type connection. Patchcords will have no pins since they are subject to damage because they simply protrude from the connector. Transceivers will be set up as jacks also, with pins inside the transceiver socket.

2. MPO vs MTP

One of the biggest areas of confusion is in regards to naming, with the cabling in question sometimes being referred to as MPO or MTP.

MTP is a particular brand of MPO-compliant fiber cables from USConec. They incorporate a number of revisions to the overall design, such as removable connector housings, while still remaining 100% intercompatible with other MPO products.

Whether they're worth the extra money is largely a matter of opinion at this point, although they have their benefits. The key point is that MTP is simply one specific implementation of MPO whose creators, undoubtedly, would like to see become more standard in the future.

Things You Need To Know About 40G QSFP+ Transceivers

QSFP+ transceiver is a hot-swappable, parallel fiber-optical module with four independent optical transmit and receive channels. These channels can terminate in another 40-Gigabit QSFP transceiver, or the channels can be broken out to four separate 10-Gigabit SFP+ transceivers.

The QSFP+ transceiver link length for either 40 Gigabit Ethernet or high density 10 Gigabit Ethernet application is up to 100 m using OM3 fiber or 150 m using OM4 fiber. These modules are designed to operate over multimode fiber systems using a nominal wavelength of 850nm. The electrical interface uses a 38 contact edge type connector. The optical interface uses an 8 or 12 fiber MTP (MPO) connector. For example, both HP JG325B compatible QSFP + transceiver and Arista QSFP-40G-SR4 compatible QSFP + transceiver from Fiberstore can achieve distance of 100m over OM3 fiber and 150 m over OM4 fiber.

Fiberstore offers a wide range of MPO connectors and 40G QSFP+ transceivers which are 100% compatible with many famous brands like Cisco, HP, Juniper, Nortel, Force10, D-link, 3Com. Besides, we also provide high-quality and cost-effective cables such as MTP trunk cables, QSFP+ breakout cable, LC to MTP jumpers, etc.

High Speed Ethernet Cabling

There is a variety of types of cables and transceiver modules available for making Ethernet connections at speeds of 1Gigabit per second and above. This article will introduce the widely used optical transceivers and cables for 1-Gigabit, 10-Gigabit and 40-Gigabit connections.

1-Gigabit Connections

• Transceivers
  Optical fiber connections are constructed with a combination of a transceiver (sometimes called a GBIC – for GigaBit Interface Converter). The transceiver accepts digital signals from the Ethernet device (switch or adapter card) and converts them to optical signals for transmission over the fiber. Although a number of different form factors for this GBIC have been defined by standards bodies, the most common is the SFP (Small Form Factor Pluggable Transceiver). The term GBIC initially was used for a specific form factor, but with the widespread adoption of the smaller SFP standard form factor, the term GBIC has fallen into the vernacular as a general term for an optical transceiver.
• Cables
  The most commonly used cable for 1Gbps Ethernet is the Category 5 (Cat5) cable with an RJ45 connector on either end. This cable can handle connections of up to about 100 M in length. For longer connections an optical fiber cable can be used.

10-Gigabit Connections

For 10-Gigabit Ethernet cabling the fiber options are very similar. The transceivers are somewhat different, as is some nomenclature. New possibilities have evolved for copper connections.

• Transceivers
  Standards bodies initially offered several options for the 10-Gigabit transceiver. The one that ultimately evolved as most popular in commercial data center usage was the XFP transceiver. XFP stands for 10–Gigabit Form Factor Pluggable. In recent years an extension of the SFP transceiver was standardized for use with 10 Gigabit Ethernet and named SFP+. SFP+ has the same mechanical characteristics as the the SFP transceiver – it just is capable of supporting the higher speed (some, but not all, SFP+ transceivers can actually operate at either 1Gbps or 10Gbps). The advantage of SFP+ was that it was smaller than the XFP form factor allowing for much more dense packaging of ports on switches.
• Fiber Cables
  10-Gigabit Ethernet fiber connections use the same optical fiber types as 1-Gigabit Ethernet. The range is less due to the higher speed and the names are similar:
  Short Range: SR -for connections of up to 300 M in length
  Long Range: LR –for connections of up to 2,000 M (2 KM) in length.
  A new option is also available, though rather rarely used:
  Extended Range: ER – for connections of up to 10,000 M (10 KM) in length.

40-Gigabit Connections

• Transceivers
  40 Gigabit optical transceivers mainly include CFP transceiver and QSFP transceiver. The most common types of QSFP/QSFP+ optical transceivers are QSFP-40G-PLR4, QSFP-40G-CSR4, 40GBASE-PLRL4, QSFP-40G-LR4, and QSFP-40G-SR4. For example, JuniperJNP-QSFP-40G-LR4compatible 40GBASE-LR4 QSFP + transceiver from Fiberstore provides 4 CWDM lanes in 1310nm and achieves a transmission distance of 10km over single mode fibers.  
• Cable Assemblies
  Cables used in 40 Gigabit Ethernet mainly include passive and active direct attach copper cables and active optical cable (AOC). The QSFP+ passive or active direct attach copper cables are designed with twinax copper cable and terminated with QSFP+ connectors. For instance, CiscoQSFP-4SFP10G-CU1Mcompatible QSFP+ to 4SFP+ passive copper cable is suitable for very short distances and offer a very cost-effective way to establish a 40-gigabit link between QSFP port and SFP+ port of Cisco switches within racks and across adjacent racks. The main difference between passive QSFP+ DAC and active QSFP+ DAC is that the passive one is without the active component. AOC is used for short-range multi-lane data communication and interconnect applications. It uses electrical-to-optical conversion on the cable ends to improve speed and distance performance of the cable without sacrificing compatibility with standard electrical interfaces.  

As the main fiber optical manufacturer and supplier in China, Fiberstore offers a full range of optical transceivers, such as SFP+ transceiver, X2 transceiver, XENPAK transceiver, XFP transceiver, SFP transceiver, GBIC transceiver, CWDM/DWDM transceiver, 40G QSFP+ & CFP, 3G-SDI video SFP, WDM Bi-Directional transceiver and PON transceiver. All our fiber transceivers are 100% compatible with major brands like Cisco, HP, Juniper, Nortel, Force10, D-link, 3Com.