40GBASE-SR4 QSFP+ Transceiver Overview

The 40G QSFP+ transceiver is a hot-swappable transceiver module which integrates 4 independent 10Gbit/s data lanes in each direction to provide 40Gbps aggregate bandwidth. 40GBASE QSFP+ transceiver provides a wide variety of high-density 40 Gigabit Ethernet connectivity options for data center and computing networks. 40G QSFP+ transceivers have various types like QSFP-40G-CSR4, QSFP-40G-PLR4, 40GBASE SR4 transceiver and so on. The following passages will mainly introduce the 40GBASE-SR4 QSFP+ transceiver.

Specifications of 40GBASE-SR4 QSFP+ Transceiver

The 40GBASE SR4 QSFP+ transceiver modules support link lengths of 100m and 150m respectively on laser-optimized OM3 and OM4 multimode fibers. It primarily enables high-bandwidth 40G optical links over 12-fiber parallel fiber terminated with MPO/MTP multifiber connectors. And also, it can be used in a 4 x 10G mode for interoperability with 10GBASE-SR interfaces up to 100m and 150m on OM3 and OM4 fibers respectively. The worry-free 4 x 10G mode operation is enabled by the optimization of the transmit and receive optical characteristics of the QSFP-40G-SR4 to prevent receiver overload or unnecessary triggering of alarm thresholds on the 10GBASE-SR receiver, at the same time being fully interoperable with all standard 40GBASE-SR4 interfaces. The 4 x 10G connectivity is achieved by using an external 12-fiber parallel to 2-fiber duplex breakout cable, which connects the 40GBASE-SR4 module to four 10GBASE-SR optical interfaces. Below is a picture of 40GBASE-SR4 QSFP+ transceiver.

40GBASE-SR4 QSFP+ module

From the above statement, it can be seen that 40GBASE-SR4 QSFP+ transceiver uses MPO (Multi-fiber Push-On) connector to support optical links. Why use MPO connectors rather than other connectors? Please keep reading the below passage and you will get an answer.

MPO Connector Used in 40GBASE-SR4 QSFP+ Transceiver

With higher speed transmission mode, 40GbE drives the data center to run at a high-density and cost-effective style. Thus, parallel optics technology is considered to be a perfect solution for transmission due to its support of 10G, 40G and 100G transmission. The IEEE 802.3ba 40G Ethernet standard offers 40G transmission a direction by using laser-optimized OM3 and OM4 multimode fibers. Parallel optical channels with multi-fiber multimode optical fibers of the OM3 and OM4 are utilized for implementing 40G Ethernet. The small diameter of the optical fibers has no problems with the lines laying, but the ports must accommodate four or even ten times the number of connectors. So the large number of connectors cannot be covered with conventional individual connectors any more. Under this situation, 802.3ba standard incorporated the MPO multi-fiber connector for 40GBASE-SR4 because MPO connector provides a smooth transition to higher Ethernet speeds with minimum disruption and without wholesale replacement of existing cabling and connectivity components.

In fact, MPO connectors have either 12-fiber or 24-fiber array. For 40GBASE-SR4 QSFP+ transceiver, a MPO connector with 12 fibers is used. 10G is sent along each channel/fiber strand in a send and receive direction and only 8 of the 12 fibers are required and provide 40G parallel transmission as shown in below figure.

40GBASE-SR4 QSFP+ transceiver

After looking through the above illustration, have you got a brief understanding of the 40GBASE-SR4 QSFP+ transceiver? Fiberstore, a leading and professional 40gbase sr4 qsfp+ manufacturers, offers high quality 40G qsfp+ transceiver including 40Gbase SR4 transceiver, 40GBASE-LR4 transceiver, Cisco QSFP-40G-SR4, etc. If you are looking for a 40G transceiver. Fiberstore would be a primary choice. For more information, please visit www.fs.com.

The use of The MPO In 10GBASE-SR and 40GBASE-SR chanels


The purpose of this document is to describe the usage and reason behind the development and characteristics of the MPO to be utilized in 10GASE-SR and 40GBASE-SR4 chanels.


MPO connectivity has become widely used throughout the industry not only to reduce cable density, but also to prepare for the migration from 10GBASE-SR to 40GBASE-SR.

With the 10GBASE-SR transmission, there are two fibers associated with the channel one fiber for transmit and one fiber for receive. This configuration is often referred to as a duplex channel. The polarity of these channels (TX to RX) is relatively easy to manage from end to end and if polarity correction is required, it is easy to accomplish in the field by rearranging the fibers in the duplexing clip. Also, when two of these connectors need to be mated, an adapter with a split sleeve is used to align the ferrules of the two connectors. Shown below is a typical 10GBASE-SR Method A channel.

10GBASE - SR Method A Channel

In an existing 10G Ethernet fiber infrastructure, LC to MPO cassettes are replaced with MPO adapter panels and LC to LC patch cords are replaced with MPO patch cords during migration to 40G Ethernet. In this example, three different types of patch cords are required for the migration: Method A/Female to Male, Method A/Male to Male, and Method B/Female to Male. Using patch cords terminated with MPO Connectors, only one type of patch cord needs to be purchased and stocked, and can be configured on the fly to replace any of the three needed patch cords.

In the 40GBASE-SR transmission, there are eight fibers associated with the channel four fibers for the TX signal and four fibers for the RX signal. With multiple fibers being utilized, the polarity of the channel becomes harder to manage from end to end. Additionally, mating of two MPO connectors is not completed with an adapter with a split sleeve but rather with alignment pins that are a fixture on the MPO connector. One MPO connect or has alignment holes (this connector is referred to as a female MPO) and the other MPO connector has alignment pins.(this connector is referred to as a male MPO).

These two connectors are mated together in a genderless MPO adapter. Figure 2 shows a typical 40GBASE-SR Method A channel.

40GBASE-SR4 Method A Channel

When using MPO based connectivity in the 10G channel, the standard, ANSI/TIA-568C.1-7, calls for a female MPO horizontal cabling in frastructure (as shown in Figure 1) and a male MPO cassette. The male MPO is located within the cassette to protect the fragile alignment pins from damage during installation. In a 40G channel configuration, cassettes are not used and therefore cannot serve to protect the pins. Consequently, in the 40G channel configuration the standard calls for male MPO horizontal cabling (as shown in Figure 2) to protect the alignment pins on the back side of the adapter module rather than have them exposed to possible damage on the end of a patch cord. Male connectors on patch cords pose an additional operational risk to QSFP+ ports should a male connector be inserted due to the QSFP+ ports being configured as male to protect the pins within the port. The following is the products about 40G QSFP+ MTP MPO to QSFP+ Assembly from Fiberstore.

MTP trunk cable

QSFP+ MTP/MPO fiber trunk cable assemblies are interconnecting QSFP+ transceivers operating within 40GBASE-SR parallel optics networks.QSFP+ transceivers utilize 12Fibres MPO/MTP interface and perform 40G transmission using 4 x 10G channels (8 fibres: 4 x TX and 4 x RX ).Fiberstore MTP/MPO QSFP+ assemblies are built with highest quality components. Standard MTP/MPO as well low loss Elite versions are offered featuring low insertion loss for demanding high speed networks where power budgets are critical.

Considering this discussion, in order to comply with the ANSI/TIA-568C.1-7 cabling guidelines and provide the optimal pin protection when migrating from a 10G to 40G cabling configuration, the MPO connectors associated with the horizontal cabling infrastructure must be changed from female to male. Given that existing MPO connectivity does not allow for this alteration in the field without significant risk of fiber or connector damage, ii seems that the cabling in the horizontal cabling infrastructure would need to be changed out.

In the Method A configuration shown in Figure 2, there are also two different MPO patch cords necessary to complete the 40G channel. Not only does the horizontal cabling MPO change from female to male, but a Method A cord and Method B cord are needed at the ends to complete the channel to ensure proper polarity.

A Method B configuration holds the same gender issues as Method A when migrating from 10G to 40G, but does not need the two different MPO patch cords to complete the channel.

Testing is another challenge present with MPO horizontal solutions. Some testers have a fixed male MPO interface while others have a fixed female MPO interface. In both cases the preferred one jumper testing method, Method B, per TIA-568-C (TIA-526-14A and TIA-526-7) cannot be used for both the male horizontal and female horizontal cabling infrastructures. In the case where the MPO interface on the tester does not match the MPO in the horizontal infrastructure, a three jumper method would need to be utilized. The three jumper method introduces more variability and possibility for error in the testing.

For example, Figure 3 shows a tester with fixed Male MPO interfaces on the source and meter units. When setting the reference, you will need to use a female to female MPO reference cord. After setting the reference, in order to test a female horizontal cabling infrastructure, a third reference cable with a male end would need to be introduced to properly test the horizontal cabling infrastructure.

In any of these cases changing either the polarity or gender of the standard MPO connector in the field is not recommended due to the complex construction of the connector. Trying to change either of these characteristics in the field is extremely difficult and may lead to damage to the fiber exposed when attempting to replace the connector housing.

MTP MPO Fiber Cable is offered for various applications for all networking and device needs like 100G/40G modules. It uses a high-density multi-fiber connector system built around precision molded MT ferrule. Fiberstore MPO fiber cables are available in UPC and APC finishes, support both multimode and single mode applications, and optional lengths available. Our MTP/MPO fiber cable is with push connector IEC 61754-7 and TIA/EIA 604-5A compliant and offer low cost per termination for high density applications. The MPO/MTP fiber cables are tested with guaranteed quality, and they can be installed easily, which saves time and money.

Plug-and-Play MPO Solutions in Fiber Cabling

As enterprises implement more fiber optic cabling to support bandwidth and storage requirements in the data center and backbone infrastructures, fiber termination methods are under intense scrutiny. Data center managers need to understand the key performance, installation, management, and cost considerations surrounding primary fiber termination methods. Each method has its own pros and cons, and the need has never been greater for comprehensive information to help data center managers make the right choice for their environment. In this white paper, you will learn the about the pros and cons of the following fiber termination methods:

  • Preterminated Plug-and-Play MPO Solutions
  • Factory-Terminated Pigtails with Splicing
  • Field Termination

The MPO connector is a high-density, multi-fiber connector that typically terminates 12 fibers in one connector approximately the same size of a one SC-style fiber connector. MPO plug-and-play cassettes include an MPO interface on one side broken out to12 individual fiber interfaces on the other side. These cassettes can be deployed in an optical distribution frame for higher density applications or in fiber panels to connect the main distribution area (MDA) to the equipment distribution area (EDA) in the data center. Plug-and-play trunk cables are round 12-fiber cables that are preterminated in the factory with MPO connectors on both ends. These trunk cables are purchased in predetermined lengths and are typically easier to manage than traditional ribbon cables. They can be quickly connected to the MPO plug-and-play cassettes at the cross-connect or interconnect in the MDA, EDA, or other areas of the data centre. This method eliminates the need for on-site fiber termination and splicing. Consequently, customers can rapidly complete fiber connections in high-density applications.


Advantages to Plug-and-play MPO Solutions

  • Reduced Labor Cost

Less time is required for plug-and-play installation vs.splicing or field termination. Less expertise and resources are required of installation staff.

  • Enhanced Performance

MPO connectors are factory terminated and tested in a clean environment with comprehensive quality control processes and documented test results that correspond to serial numbers stamped on each assembly.

  • Better Manageability and Density

MPO Cassette offers the highest density for fiber connections, maximizing space savings in the data centre. They are easily deployed in a cross-connect scenario for better cabling management.

  • Better Prepared for Beyond 10-Gigabit

40-Gbps and 100-Gbps speeds on multimode fiber will likely require parallel optics where data is transmitted and received over multiple fibers. MPO connectors are more prepared for this technology because they already encompass multiple fibers.

Disadvantages to Plug-and-play MPO Solutions

  • Inreased Material Cost

Plug-and-play MPO solutions are typically more expensive than other options.

  • Higher Return Loss and Insertion Loss

The additional mated pair increases the return loss and insertion loss. Insertion link loss with MPO solutions can account for an addition 0.5dB per cassette, requiring careful planning of the loss budget.

  • Limited Access to Individual Circuits

With 12-fiber MPO trunk cable, individual circuit access to backbone cabling is limited. However, when used in a cross-connect scenario, individual circuits should not need to be accessed once installed.

  • Pedetermined Lengths Required

MPO trunk cables are made to order in predetermined lengths, so lengths and lead-time must be part of the planning process. In addition, measurements need to be exact or slack storage will be required.

fiber trunk cable

FS.COM MPO Cassette provides seamless plug-and-play structured cabling solution especially suitable for high density data center environment. By integrating with FS.COM Plug-and-play rackmount enclosure, it connects between the MPO interfaces on the backbone trunk cable to the generic LC interface that will directly link to the equipment.

The cassette is designed with a user friendly snap-in modular style, pre-installed with factory-terminated and factory-tested 12- or 24-fiber MPO to LC assembly with assured best performance on optical loss. The convenient plug-and-play feature offers a flexible, quick-deployment solution with maximum reliability and durability, which offers a simple and efficient choice in optimizing your network system.

FS.COM manufactures a wide range of MTP/MPO products including MPO/MTP fiber cables, MTP/MPO Harness Cable, MTP/MPO trunk cable, MTP/MPO cassettes. Multi fiber ferrule connections used in high-density backplane and Printed Circuit Board (PCB) applications in data and telecommunications systems. High density MTP/MPO trunk cables with up to 144 fibers. The MPO fiber cable connector offers up to 12 times the density of standard connectors, providing significant space and cost savings.