Author: Fiber-MART.COM

40GBASE QSFP+ (quad small form factor pluggable) portfolio offers customers a wide variety of high-density and low-power 40 Gigabit Ethernet connectivity options for data center, high-performance computing networks, enterprise core and distribution layers, etc. And each kind of 40GBASE QSFP+ transceiver has its special applications. 40GBASE-LR4 QSFP+ transceiver is a common 40 Gigabit Ethernet connectivity option. Here is some basic information about 40GBASE-LR4 QSFP+ transceiver.

Introduction

40GBASE-LR4 QSFP+ module supports link lengths of up to 10 kilometers over a standard pair of G.652 single-mode fiber with duplex LC connectors. The 40 Gigabit Ethernet signal is carried over four wavelengths. Multiplexing and demultiplexing of the four wavelengths are managed within the device. The letter “L” stands for long, the “R” denotes the type of interface with 64B/66B encoding and the numeral 4 indicates numeral 4 indicates that the transmission is carried out over a ribbon fiber with four singlemode fibers in every direction. Each lane has a 10 Gbit/s data rate. 40GBASE-LR4 QSFP+ transceiver modules are compliant with the QSFP+ MSA and IEEE 802.3ba 40GBASE-LR4. The picture below shows a Mellanox MC2210511-LR4 compatible 40GBASE-LR4 QSFP+ transceiver.

Two Types of 40GBASE-LR4 QSFP+ Transceiver

There are mainly two of 40GBASE-LR4 QSFP+ transceivers, 40GBASE-LR4 CWDM (coarse wavelength division multiplexing) QSFP+ transceiver and 40GBASE-LR4 PSM (parallel single-mode fiber) QSFP+ transceiver. This part mainly talks about these two 40GBASE-LR4 QSFP+ transceiver types.

40GBASE-LR4 CWDM QSFP+ transceiver, such as QSFP-40GE-LR4, contains a duplex LC connector for the optical interface. It can support transmission distance of up to 10km. A 40GBASE-LR4 CWDM QSFP+ transceiver converts 4 inputs channels of 10G electrical data to 4 CWDM optical signals by a driven 4-wavelength distributed feedback (DFB) laser array, and multiplexes them into a single channel for 40G optical transmission. Then the receiver module accepts the 40G CWDM optical signals input, and demultiplexes it into 4 individual 10G channels with different wavelengths.

40GBASE-LR4 PSM QSFP+ transceiver is a parallel single-mode optical transceiver with an MTP/MPO fiber ribbon connector. It also offers 4 independent transmit and receive channels, each capable of 10G operation for an aggregate data rate of 40G. The transmitter module accepts electrical input signals compatible with common mode logic (CML) levels. All input data signals are differential and internally terminated. The receiver module converts parallel optical input signals via a photo detector array into parallel electrical output signals. The receiver module outputs electrical signals are also voltage compatible with CML levels.

Applications

QSFP-40GE-LR4 supports 40GBASE Ethernet rate only, whereas the QSFP-40G-LR4 supports OTU3 data rate in addition to 40GBASE Ethernet rate. 40GBASE-LR4 QSFP+ transceivers are most commonly deployed between data-center or IXP sites with single mode fiber.

fiber-mart.com offers customers a wide variety of 40GBASE-LR4 QSFP+ transceivers for your high-density and low-power 40 Gigabit Ethernet connectivity options, including 40GBASE-LR4 CWDM QSFP+ transceiver and 40GBASE-LR4 PSM QSFP+ transceiver, like Cisco QSFP-40GE-LR4 40GBASE-LR4 QSFP+ transceiver. fiber-mart.com also provides wide brand compatible 40G QSFP+ transceivers, such as Brocade QSFP+, Dell QSFP+, Juniper QSFP+, Mellanox QSFP+, and HP QSFP+. Each fiber optic transceiver provided by fiber-mart.com has been tested to ensure its compatibility and interoperability. Please rest assured to buy.

As we know, fiber optic patch cords are capped at both ends with fiber optic connectors to allow them to be rapidly and conveniently connected to telecommunication equipment. Fiber optic connector is one of those high quality ceramic components used to achieve accurate and precise connections of the fiber ends. It is a simple device which allows fiber links to be readily connected and disconnected.

How to install fiber optic connectors to optical fibers so that they can achieve accurate and precise connections? The method for attaching fiber optic connectors to optical fibers varies based on connector types. Installation ways of fiber optic connectors largely depends on the connector types. Generally, connectors can be categorized into no-epoxy/no-polish connectors and epoxy-and-polish connectors. The following text elaborates on how to install these two kinds of connectors respectively.

No-epoxy/no-polish Connector Installation

How to install no-epoxy/no-polish (NENP) connectors to optical fibers? A no-epoxy/no-polish connector includes an precisely polished endface. When installing an NENP connector, there is no need to use an epoxy or to polish the endface. The field fiber is mechanically spliced to a factory-cleaved fiber stub. The following picture is an illustration of  no-epoxy/no-polish connector installation.

The installation process begins with preparing the field fiber, which is done by stripping the protective coating down to the bare glass. Once the fiber is cleaned, it is then cleaved with a precision cleaver. Next step is to insert the field fiber into the connector until it is seated against the factory-stubbed fiber and locked into place mechanically by a rotating cam or other means. Typically this step is achieved by using a tool that holds the connector and activates the mechanical splice by a button or lever.

Epoxy-and-polish Connector Installation

How to install epoxy-and-polish (EP) connectors to optical fibers? The most common types of EP connectors use heat- or anaerobic-curing techniques. A heat-cure connector uses heat to harden an epoxy, which takes several minutes. An anaerobic EP connector uses a two-part epoxy, a hardener that is inserted into the connector and an activator on the fiber.

To install an EP connector, an epoxy must be inserted into the connector ferrule first to form a bond between the field fiber and the connector’s ferrule, and then the endface needs to be hand-polished. Next, the field fiber is stripped down to the bare glass and cleaned. If the connector is heat-cure, the fiber is inserted into the connector and placed in an oven for the epoxy to cure. If the type of connector is anaerobic, the bare fiber is painted with an activator and inserted into the connector. Once the epoxy has been cured, the fiber stub which is protruding above the ferrule is scribed and removed. The final step is to polish the endface of the connector using a fixture and several different polishing films.

Notes for Fiber Optic Connector Installation

Besides different installation methods for different connector types, several things need to be paid attention to when installing fiber optic connectors, especially when a fiber patch cord has two different types of connectors, such as LC-SC fiber optic patch cord or FC-ST fiber optic patch cord.

Any problems with a connector, such as poor installation and uncleanness, can greatly influence the transmission and reception of the light power. And such problems may render the fiber optic system inoperative. So it is very necessary to know something about installation of fiber optic connectors.

With the increasing demand for network capacity, upgrades must be planned with an eye to the future. Installing 50μm multimode fiber today brings immediate benefits of longer cable reach and improved light loss budget margins, and prepares the network for future upgrades.

Fiber jumpers continue to provide a cost-effective cabling solution for data centers, local area networks (LANs), and other enterprise applications. Singlemode fiber optic patch cords and multimode fiber optic patch cords are two options. Compared to singlemode fiber, multimode fiber has a large diameter core, which allows multiple wavelengths of light traveling in the fiber core at the same time. Multimode fiber optic patch cord comes with two core sizes: 50 micron and 62.5 micron. And this article will talk about these two core sizes of multimode fiber optic cables.

Overview

The numbers 50µm and 62.5µm refer to the diameters of the glass or plastic core, the part of the fiber that carries the light which encodes your data. The dimensions are sometimes specified as 50/125μm and 62.5/125μm, to include the diameter of the cladding, which confines the light to the core because it has a lower index of refraction. You can use both in the same types of networks, although 50µm cable is recommended for premise applications, like backbone, horizontal, and intrabuilding connections. They both can use either LED or laser light sources. The main difference between 50µm and 62.5µm cable is in bandwidth, 50µm cable features three times the bandwidth of standard 62.5µm cable, particularly at 850nm. The 850nm wavelength is becoming more important as lasers are being used more frequently as a light source. Other differences are distance and speed. 50µm cable provides longer link lengths and higher speeds in the 850nm wavelength.

62.5µm Multimode Fiber Optic Patch Cords

OM1 fiber optic cable is the 62.5/125 multimode fiber cable. OM1 fiber has a bigger core diameter, which makes it better at concentrating the light and bend-resistance. OM1 fiber was the indoor cabling standard chosen by AT&T, ANSI and IBM. For OM1 fiber cable, the max attenuation is 3.5dB/km working at 850nm, 1.5dB/km at 1300nm. Overfilled launch of OM1 fiber optic cable at 850nm is 200MHz*km, at 1300nm is 500MHz*km. Today, OM1 fiber optic cables are still a popular indoor use multimode fiber optic cable.

50µm Multimode Fiber Optic Patch Cords

50µm fiber includes OM2, OM3, OM4. OM2 fiber optic cable refer to the commonly used 50/125 traditional multimode fiber cable. OM1 and OM2 are both orange jacketed cable, and you cannot judge from the outer diameter to identify OM1 and OM2 fiber cable, because the 50/125 and 62.5/125 refer not to whole cable diameter but to the fiber inside. OM2 multimode fiber cables are used in fiber optic telecommunications and high speed transmission systems that require simultaneous, bi-directional data transfer.

OM3 cable and OM4 cable are both optimized for laser based equipment that uses fewer modes of light. As a result of this optimization, they are capable of running 10 Gigabit Ethernet at lengths up to 300m and 550m respectively. OM4 is completely backwards compatible with OM3 fiber and shares the same distinctive aqua jacket. OM4 was developed specifically for VSCEL laser transmission. OM4 multimode fiber optic cable is the highest level of multimode fiber optic cable that you can use. They can be used in networks where an overwhelming or extreme amount of data transfers will take place.

Which One Should You Choose?

Given its superior technical characteristics for high-speed links, 50μm fiber is the clear choice for new multimode fiber links in most circumstances. OM3-grade, high-bandwidth 50/125-micron fiber cable increases the flexibility of network designs and achieves data transfer rates up to 10Gbps at the lowest available cost. 50μm multimode fiber is the medium of the future, with 62.5μm fiber being supported chiefly for legacy purposes. However, the majority of the fiber deployed in the world today is 62.5μm, so backward compatibility is an important concern. On the other hand, there are no technical drawbacks to using different fiber types in separate network links, as long as the ports at both ends of the link are compatible with the cable. In a word, installing 50μm fiber for new network links is a good investment for future growth.

40GbE (Gigabit Ethernet) is Ethernet standard developed by the IEEE 802.3ba, enabling the transfer of Ethernet frames at speeds of up to 40 gigabits per second (Gbps). Now 40 Gigabit Ethernet is becoming more and more popular, suitable for high-speed, high-demand, and computing applications. For a 40GbE network, transceiver modules are one of the most basic components for transmission, used to plugged into either network servers or various of components such as interface cards and switches. 40GbE transceivers are being developed along several standard form factors. Some basic knowledge of 40GbE transceivers will be provided in the following text.

The CFP (C form-factor pluggable) transceiver features twelve transmit and twelve receive 10Gbps lanes to support one 100GbE port, or up to three 40GbE ports. Its larger size is suitable for the needs of single-mode optics and can easily serve multimode optics or copper as well. The following picture shows a CFP transceiver. 40GBASE CFP transceiver modules are hot-swappable input/output devices that plug into a 40 Gigabit Ethernet CFP port of a switch or router. CFP modules offer customers versatile 40 Gigabit Ethernet connectivity options in core and distribution layers of data center, enterprise, and service provider networks. Main features of 40GBASE CFP modules include:

Support for 40GBASE Ethernet and OTU3 standards

Support for “pay-as-you-populate” model

Support for digital optical monitoring (DOM)

Variety of interface choices for 40 Gigabit Ethernet connectivity

Interoperability with respective industry IEEE- and/or OTU3-compliant interfaces

Support for the Cisco quality identification (ID) feature, which enables a Cisco switch or router to identify whether the module is certified and tested by Cisco

CXP Transceiver

The CXP transceiver form factor also provides twelve lanes in each direction but is much smaller than the CFP and serves the needs of multimode optics and copper. The Roman number X means that each channel has a transmission rate of 10 Gbps. CXP is a kind of hot-pluggable transceiver with data rate up to 12×10 Gbps. It provides twelve 10 Gbit/s links suitable for single 100 Gigabit Ethernet, three 40 Gigabit Ethernet channels, or twelve 10 Gigabit Ethernet channels or a single Infiniband 12× QDR link. The C is the Roman numeral for 100 as a memory aid.

QSFP/QSFP+ Transceiver

The QSFP/QSFP+ (quad small-form-factor pluggable) is similar in size to the CXP and provides four transmit and four receive lanes to support 40GbE applications for multimode and single-mode fiber and copper today. It is the most popular interface of 40G transceivers now. Two main types of QSFP+ transceivers used in the data center are QSFP-40G-SR4 and QSFP-40GE-LR4. The following picture shows an Arista QSFP-40G-SR4 QSFP+ transceiver and a Cisco QSFP-40GE-LR4 QSFP+ transceiver. QSFP-40G-SR4 is used in 4x10G mode along with ribbon to duplex fiber breakout cables for connectivity to four 10GBASE-SR optical interfaces. 40GBASE-LR4 QSFP+ module supports link lengths of up to 10km over a standard pair of G.652 single-mode fibres with duplex LC connectors. In addition, there are other types of QSFP+ modules, such as QSFP-40G-ER4, 40GBASE-PLRL4, etc. Main features of 40GBase QSFP+ modules include:

Support for 40GBASE Ethernet

Flexibility of interface choice

Hot-swappable input/output device that plugs into a 40-Gigabit Ethernet QSFP+ switch port

Interoperable with other IEEE-compliant 40GBASE interfaces available in various form factors

Support for “pay-as-you-populate” model

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.

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.

Conclusion

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. fiber-mart.com 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.