Tag Archives: 40GBASE-CSR4

Things to Know about 40GBASE-SR4 QSFP+ Modules

With the growing demand for high data rates, 40 Gigabit Ethernet (GbE) is now becoming more and more widely adopted. For a 40 GbE network application, precise connectivity is crucial. 40G QSFP (quad small form factor pluggable) portfolio offers customers a wide variety of high-density and low-power 40 Gigabit Ethernet connectivity options. Among them, 40GBASE-SR4 QSFP+ transceiver is a common 40 GbE connectivity option. And here are some things that you need to know about 40GBASE-SR4 QSFP+ transceivers.


40GBASE-SR4 is a fiber optic interface for multimode fiber of OM classes 3 and 4 with four parallel OM3 or OM4 fibers in both directions. “S” means short, indicating that it is an interface for short distances. The “R” denotes the type of interface with 64B/66B encoding and the numeral 4 indicates that the transmission is carried out over a ribbon fiber with four multimode fibers in every direction. Each lane has a 10 Gbit/s data rate. 40GBASE-SR4 QSFP+ modules usually use a parallel multimode fiber (MMF) link to achieve 40G. It offers 4 independent transmit and receive channels, each capable of 10G operation for an aggregate data rate of 40G over 100 meters of OM3 MMF or 150 meters of OM4 MMF. It primarily enables high-bandwidth 40G optical links over 12-fiber parallel fiber terminated with MPO/MTP multifiber female connectors.

40GBASE-SR4 QSFP+ module can also be used in a 4x10G mode for interoperability with 10GBASE-SR interfaces up to 100 and 150 meters on OM3 and OM4 fibers, respectively. The worry-free 4x10G mode operation is enabled by the optimization of the transmit and receive optical characteristics to prevent receiver overload or unnecessary triggering of alarm thresholds on the 10GBASE-SR receiver, and at the same time is completely interoperable with all standard 40GBASE-SR4 interfaces. The 4x10G connectivity is achieved using an external 12-fiber parallel to 2-fiber duplex breakout cable, which connects the 40GBASE-SR4 module to four 10GBASE-SR optical interfaces. The picture below shows a Mellanox MC2210411-SR4 compatible 40GBASE-SR4 QSFP+ transceiver.

Mellanox MC2210411-SR4 Compatible 40GBASE-SR4 QSFP+ Transceiver

40GBASE-SR4 QSFP+ Module vs 40GBASE-CSR4 QSFP+ Module

40GBASE-CSR4 QSFP+ module is similar to the 40GBASE-SR4 interface extends supported link lengths to 300m and 400m respectively on laser-optimized OM3 and OM4 multimode fiber cables. Each 10-gigabit lane of this module is compliant to IEEE 10GBASE-SR specifications. This module can be used for native 40G optical links over 12-fiber ribbon cables with MPO/MTP connectors, or in 4x10G mode with ribbon to duplex fiber breakout cables for connectivity to four 10GBASE-SR interfaces. Maximum channel insertion loss allowed is respectively 2.6dB over 300m of OM3 cable or 2.9dB over 400m of OM4 cable.


Fiberstore offers you a wide variety of 40GBASE-SR4 QSFP+ transceivers for your high-density and low-power 40 Gigabit Ethernet connectivity options branded by many famous companies like Cisco, Juniper or HP. And we also provide other compatible 40G QSFP+ transceivers, such as 40GBASE-LR4 QSFP+ transceiver, 40GBASE-ER4 QSFP+ transceiver, 40GBASE-CSR4 QSFP+ transceiver, etc. Every fiber optic transceiver provided by Fiberstore has been tested to ensure its compatibility and interoperability. You can buy from us with confidence.

Parallel Optics Technology Overview

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.

Introduction to MPO/MTP Technology in 40 GbE

The increasing demands of bandwidth and high speed drive the emergence of 40 GbE, and even up to higher in the future. And the high-speed transmission requires high-density data center as the increasing created data need amount of cables and devices which take a lot of space and cost. Data centers have to achieve ultra-high density in cabling to accommodate all this cabling in the first place. Multimode fiber optics is the medium of the future for satisfying the growing need for transmission speed and data volume over short distances. Ultra-parallel connections involve tougher requirements in terms of the components and the handling of the connectors. The MPO/MTP technology has proven to be a practical solution. This article provides introductory information on MPO/MTP technology in 40 GbE.

MPO/MTP—Multi-fiber Connectors for High Port Density

Parallel optical channels with multi-fiber multimode optical fibers of the categories OM3 and OM4 are used for implementing 40 GbE. The small diameter of the optical fibers poses no problems in laying the lines, but the ports suddenly have to accommodate four or even ten times the number of connectors. This large number of connectors can no longer be covered with conventional individual connectors. That is why the 802.3ba standard incorporated the MPO multi-fiber connector for 40GBASE-SR4. It can contact 12 or 24 fibers in the tiniest of spaces. Next part describes this type of connector.

12 Fibers 10G OM4 Harness Cable, 12 Strands, MPO-HD to LC-HD Push Pull TAB Connector

MPO Connectors: Structure and Function

The MPO connector (known as multi-fiber push-on and also as multi-path push-on) 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. Eight fibers are needed for 40 GbE, which means four contacts remain non-interconnected in each case. MPO connectors and MTP (mechanical transfer push-on) connectors are no longer terminated on site because of the delicate multi-fiber structure and narrow tolerances involved. MPO/MTP connectors are therefore sold already terminated together with trunk cables. With this arrangement, customers have to plan line lengths precisely but are also assured top quality and short installation times. To achieve lower tolerances and better attenuation values, the American connectivity specialist US Conec developed the MTP connector. It has better optical and mechanical quality than the MPO. An MTP connector consists of a housing and a separate MT ferrule. The MT ferrule is a multi-fiber ferrule in which the fiber alignment depends on the eccentricity and positioning of the fibers and the holes drilled in the centering pins. The centering pins help control fiber alignment during insertion. Since the housing is detachable, the ferrules can undergo interferometric measurements and subsequent processing during the manufacturing process.


MPO/MTP connectors and fiber cables as the important part of the multi-fiber connection system, are designed for the reliable and quick operations in data centers. Fiberstore manufactures and distributes a wide range of MTP/MPO cable assemblies including trunk cables, harness cables and cassettes (or patch panels). And we also offer other kinds of transceiver and cable choices for your 40GbE applications, for example, HP JG709A 40GBASE-CSR4 QSFP+ transceiver, and Juniper QFX-QSFP-DAC-3M QSFP+ to QSFP+ passive copper cable, etc. Futhermore, customized service such as optional fiber counts, cable types and lengths are available.