Things to Know About 40G QSFP+ AOC

As the demand for reliable, efficient and fast data transfer continues to heat up, the need for a more capable alternative to traditional copper cables also grows parallel with it. Achievements in network technologies have ushered in a new era with higher speed connectivity, thus migration from 10G to 40G nowadays is no longer a fresh topic but an irresistible trend. The active optical cable (AOC), since it was introduced in 2007, has been considered to be an optimum option for 40G support connectivity. This article will explain some vital elements in related to 40G QSFP+ AOC in detail.

40G QSFP+ AOC Description

40G QSFP+ AOC, as the name indicates, is a type of active optical cable used for 40G networks and applications. It is terminated with 40G QSFP+ connector on one end, and on the other end, it can be terminated with QSFP+ connector, SFP+ connector or LC connector etc. The QSFP+ optical modules provide four parallel full-duplex transmit and receive channels, each capable of 10Gbps operation and in total 40Gbps aggregate bandwidth of at least 100 m over multimode fiber.

With a bit error rate (BER) exponentially better than that of copper cables, along with being lighter and with a tighter bend angle, AOCs have since become mass-produced for data centers and server rooms all over the world.


How Does AOC Work?

The feature that distinguishes AOCs from traditional types of connectors is the fact that data passes through optical fiber lanes as opposed to copper, while maintaining a traditional electrical connectivity interface. Besides, optical cable possess a greater capability to carry a high-speed signal over longer distances than any other types of cable, without compromising signal integrity. Not to mention that it ensures data security and non-conductivity.

All active optical cables are comprised of four main functional parts:

1. High-density connector: The form factor of the connector equipped to either side of the optical fiber cable can come in many variants to fulfill a variety of functions, whether in QSFP+ format for data centers and server rooms or HDMI format for consumer entertainment.

2. Ribbon optical fiber cable: A multi-channeled optical fiber cable (that could come in multi or single-mode) ranging from 1 to 100 meters in length.

3. Full-duplex AOC transceiver: An optical transceiver is embedded into either side of the optical cable, two optical-electrical and electrical-optical converters on either side of the cable.

4. MPO optical connector: A connector that is permanently fixed to the form factor shell and fiber, designed to shield the optical interface from external interference.

Diagram of AOC

Comparison Between 40G QSFP+ AOC and QSFP+ Optics

Currently, 40G QSFP+ AOC is becoming increasingly popular in data centers, especially those are supposed to accommodate massive and high density bandwidth. Then, how dose 40G QSFP+ AOC differ from standard QSFP+ optics? And what we can benefit from employing 40G QSFP+ AOC? Here, we simply make a comparison between them from the perspective of total cost, insertion loss and return loss.

Cost—by adopting 40G QSFP+ AOC to your existing infrastructure, there is no need to use extra fiber patch cables. So, it generally costs less when compared with QSFP+ optic modules. Let’s just take QSFP+ to QSFP+ AOCs for example, it is usually employed to very short distance data transmission while offers a rather cost-effective way to establish 40G links between QSFP ports of switches within racks and across adjacent racks. Moreover, with 40G QSFP+ AOC, you will be free from cleaning the optical connectors as well as from termination plug and test when troubleshooting, which is time-saving and cost-efficient.

Insertion loss and return loss—when considering the repeatability and interchangeability performances within the same transmission distance, 40G QSFP+ AOC is superior to that of QSFP+ optics. Because when different fiber optic patch cables plug into the module, it will have the different insertion loss and return loss, which is the same even for the same module. However, an AOC is more stable and has better swing performance than other QSFP+ optics in this situation.


The 40G QSFP+ AOC is a high performance, low power consumption integrated cable for short-range multi-lane data transmission and interconnect applications. It has been widely used in high-density connectivity data centers to upgrade the current network equipment. 40G QSFP+ AOC also offers an optimum solution for high-performance computing and storage applications. So one can rely on 40G QSFP+ AOCs when designing for higher speed and more reliable network connectivity. For more detailed products information and interconnect solutions, please visit

MPO/MTP Fiber Cabling Basics

With the ever increasing need for even greater bandwidth in data centers, multi-mode fiber cables (MMFs) have proven to be a practical optical solution to support such fast-changing and fast-growing bandwidth demand. MTP/MPO fiber cabling, ideal for quick and reliable MMF connectivity, provide an effective way for 40GbE network solutions, ensuring a high-performance and high-speed network. This blog includes basic information about MPO/MTP fiber cabling solutions.

MTP/MPO Connector Background

The term MTP is a registered trademark of US Conec used to describe their connector. The US Conec MTP product is fully compliant with the MPO standards. As such, the MTP connector is a MPO connector.

MTP/MPO Fiber Cabling System Introduction

MTP/MPO fiber cables, as an important part of the MPO/MTP cabling system, are designed to go on reliable and quick operations for the multi-fiber connection system in data centers. Each MTP fiber cable contains 12 fibers or 6 duplex channels in a connector, thus requiring less space. Besides, MTP/MPO fibers are manufactured with outstanding optical and mechanical properties, which makes them able to offer more improved scalability. What’s more, it is easy to have cable management and maintenance on them. Generally speaking, MTP/MPO fiber cables can save a lot of money and space to some extent.

MTP/MPO Fiber Cabling Categories

When it come to types, MTP/MPO fiber cables fall on MTP/MPO trunk cables and MTP/MPO harness cables.

MTP/MPO trunk cables, available in 12-144 counts, are intended for high-density application. By using MTP/MPO trunk cables, the installation of a complete fiber optic backbone is accessible without any field termination.

MTP/MPO harness cables, also called MTP/MPO breakout cables or MTP/MPO fanout cables, available in 8-144 counts, are used for breaking out the MTP into several connections. They provide connection to equipment or panels that are terminated with other standard connectors. As terminated with MTP/MPO connectors on one end and standard LC/FC/SC/ST/MTRJ connectors (generally MTP to LC) on the other end, these cable assemblies can meet a variety of fiber cabling requirements.

MPO/MTP Fiber Cabling for 40GbE

The Institute of Electrical and Electronics Engineers (IEEE) 802.3ba 40 Ethernet Standard was ratified in June 2010. The IEEE 802.3ba standard specifies MPO connectors for standard-length MMF connectivity. MMF employs parallel optics using MPO interconnects for 40GbE transmission. More specifically, 40G is implemented using eight of the twelve fibers in a MPO connector. Four of these eight fibers are used to transmit while the other four are used to receive. Each Tx/Rx pair is operating at 10G.

Fiberstore MPO-based fiber cabling solutions provide a fast , simple and economical way for 40G applications. Certainly, Fiberstore 40G fiber cabling solutions are not limited to MPO/MTP fiber cables. Copper cables are also recommended. Take CAB-Q-Q-1M for example, Arista CAB-Q-Q-1M is the QSFP+ to QSFP+ passive copper cable assembly for 40G links. Or one of other Fiberstore 40G fiber cabling products: JG329A, Fiberstore compatible HP JG329A runs over passive breakout copper cable for 40-gigabit links.

MTP/MPO Jumpers

The MTP jumpers serve to create the connection between the device ports and the structured cabling via the connector panel.


High-density MTP/MPO fiber cabling plays a significant part in cabling structure, suitable for telecommunications. Fiberstore provides both single-mode and multi-mode MPO and MTP fiber cables, as well as other MTP/MPO cable assemblies, including trunk cables, harness cables and jumpers. Customized products are also available upon your request. For more information about MPO/MTP fiber cables as well as 40G fiber cabling products (like Arista CAB-Q-Q-1M and HP JG329A mentioned above), please visit Fiberstore.

40G Needed for Data Center Networks

Driven by growing bandwidth and network performance demand, data center network infrastructure is witnessing a transformation. As technology evolves, standards are completed to define data rates such as 40 Gigabit Ethernet (GbE) to meet such demands of high networking speed and performance. 40GbE addresses physical layer specifications for communication across backplanes, copper cabling, single-mode fiber(SMF), and multi-mode fiber (MMF).

The Need for Higher Speed – 40G

1G and 10G data rates are not adequate to meet the future needs of high-bandwidth applications. The requirement for higher data rates is being driven by many factors. Switching and routing, virtualization, convergence and high-performance computing environments are examples of where these higher network speeds will be required within the data center environment. Additionally, Internet exchanges and service provider peering points and high-bandwidth applications, such as video-on-demand driving the need for a migration from 10G to 40G interfaces.

40G Physical Layer Alternatives

40GbE standards already exist for SMF, MPO based MMF, as well as copper cables. Listed below are three physical layer solutions for 40GbE.

Single-mode Fiber

Due to its long reach and superior transmission performance, SMF is specified for carrying 40Gbps data up to a distance as long as 10km (40GBASE-LR4). The physical layer electronics and optics consist of four channels, each carrying 10Gbps data with different wavelengths. When there is no need to consider budget or the link distances are long, SMF is the preferred option for 40GbE in data center networks.

Multi-mode Fiber

MMF with parallel optics MPO interface is the most popular medium for 40GbE today (40GBASE-SR4). Take F5-UPG-QSFP+ for example, Fiberstore compatible F5 Networks F5-UPG-QSFP+ (figure shown below) is a 40GBASE-SR4 QSFP+ transceiver with MPO connectors. It supports link lengths of 100m and 150m, respectively, on OM3 and OM4 MMFs at a wavelength of 850nm in a data center network. (OM3 and OM4 fibers were selected as the only MMFs for 40G consideration.)

Copper Twinax

For short reach channels up to a length of 7m, 40GBASE-CR4 standard specifies use of twinax copper cable assembly. One typical application of this kind of copper cable is in 40G QSFP+ direct attach cable (DAC). For instance, Fiberstore compatible Brocade 40G-QSFP-C-0101 is the QSFP+ to QSFP+ passive copper cable assembly for very short distances.

40G Transceivers

40G transceivers were developed along several standard form factors. The C Form-Factor Pluggable (CFP) transceiver features 12 transmit and 12 receive 10-Gbps lanes to support one 100 Gigabit Ethernet port, or up to three 40 Gigabit Ethernet ports. Its larger size is suitable for the needs of single-mode optics and can easily serve multi-mode optics or copper as well. The CXP transceiver form factor also provides 12 lanes in each direction, but is much smaller than the CFP and serves the needs of multi-mode optics and copper. The Quad Small-Form-Factor Pluggable (QSFP) is similar in size to the CXP and provides four transmit and four receive lanes to support 40 Gigabit Ethernet applications
for multi-mode fiber and copper today.


40GbE supports high-speed switching, routing, and application functions in data centers. It provides optimized performance in meeting data center requirements. As a professional fiber optic products supplier and manufacturer, Fiberstore offers various 40GbE products, like 40G transceivers, and 40G cabling available both in fiber and copper. You can visit Fiberstore for more information about 40GbE solutions.