Category Archives: Fiber Optic Connector

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.

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. 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.

Fiber Optic Connectors―an Essential Part of Fiber Optic Patch Cords

Fiber optic patch cord is a fiber optic cable capped at both ends with fiber optic connectors to allow it to be rapidly and conveniently connected to telecommunication equipment and to achieve accurate and precise connections. Fiber optic connector is a very important part of the fiber optic patch cable. This article mainly talks about what fiber optic connector is, four common types of fiber optic connectors and its relationship with fiber optic patch cables.

What Is Fiber Optic Connector?

This question can be answered in two ways. Functionally, a fiber optic connector terminates the end of an optical fiber, and provides a separable connection between two elements of an electronic system without unacceptable signal distortion or power loss. Structurally, every connector includes several parts, two permanent interfaces, the contact springs in each half of the connector, the separable interface and the connector housing which maintains the location of the contacts and isolates them from one another electrically. The connectors mechanically couple and align the cores of fibers so light can pass. To achieve less light loss, more and more better connectors are made to provide more accurate misalignment of the fibers.

Four Common Types of Fiber Optic Connectors

Connector types of the patch cable must match the patch panels and equipment so that the patch cable can function well. There are many different connectors in use for fiber optic patch cords. The text below is a brief overview of four common connector types. The following picture shows some common types of fiber optic connectors.

Fiber Optic Connector

LC connector is a small form factor plastic push/pull connector with a 1.25mm ferrule. LC was first developed by Lucent. LC connector has a locking tab and a plastic housing and provides accurate alignment via its ceramic ferrule. LC has been referred to as a miniature SC connector.

SC connector is a plastic push/pull connector with a 2.5mm ferrule. It requires less space in patch panels than screw on connectors. For its low cost, simplicity and durability, SC connector is the second most commonly used type for polarization maintaining (PM) connections. Like LC connector, SC connector also has a locking tab and provides accurate alignment via its ceramic ferrule.

FC connector is a metal screw on connector with a 2.5mm ferrule. It is extensively used at the interfaces of test equipment due to its ruggedness. FC connector is the most common connector used for PM connections. And it features a metal housing, a position locatable notch and a threaded receptacle. FC connectors are nickel-plated.

ST connector is a metal bayonet coupled connector with a 2.5mm ferrule. It can be inserted into and removed from a fiber optic cable both quickly and easily. ST connectors are nickel-plated, keyed, spring-loaded and constructed with a metal housing. It has push-in and twist types.

All these four types of fiber optic connectors have different constructions and their respective applications. And there are many other kinds of fiber optic connectors, such as MU, MTRJ, E2000, SMA, etc. One important criterion for choosing fiber patch cord is to choose one with the most appropriate connector type that meets your needs.

Fiber Optic Connectors and Fiber Optic Patch Cords

Fiber optic connector is an essential part of fiber patch cords. Generally, many fiber optic connectors can be manufactured for both single mode and multi-mode, simplex and duplex fiber patch cables. And fiber optic patch cord can have the same or different connectors at its both ends. For example, LC to LC fiber cable is a fiber patch cable with an LC connector on each end, or SC to LC patch cord is a fiber patch cable with an LC connector on one end and an SC connector on the other end.

How to Install Fiber Optic Connectors?

As we know, fiber optic patch cord is capped at both ends with fiber optic connectors to allow it 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.

No-epoxy-no-polish-Connector

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 ST-LC fiber patch cable or FC-SC fiber optic patch cord.

  • The bared fiber must be thoroughly cleaned with isopropyl alcohol.Never clean the fiber with a dry tissue.Before the connection is made, the end of each fiber must have a smooth finish that is free of defects such as hackles, lips, and fractures.
  • The cable should be cut about one inch longer than the required finished length.
  • Be sure to use strippers made specifically for use with fiber rather than metal wire strippers because damage can occur and then weaken the fiber.

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.

The Basics of Fiber Optic Connectors

In a fiber optic system, it is essential to join two fibers together with low signal attenuation while maintaining low reflection levels. Fiber optic connectors are used as the mechanical and optical means for cross connecting fibers and linking to fiber optic transmission equipment. Here is some basic information about fiber optic connectors.

Configurations of Optical Connector

Fiber optic connectors mechanically couple and align the cores of fibers so light can pass. To achieve less light loss, more and more connectors are made to provide more accurate connection of the fibers. Every connector includes several parts, two permanent interfaces, the contact springs in each half of the connector, the separable interface and the connector housing which maintains the location of the contacts and isolates them from one another electrically. The most important element of the connector plug is the ferrule, which provides the precise alignment and centering of the optical fiber. Ferrules can be made of ceramic, metal, glass or plastic. Zirconia ceramic ferrules or ceramic ferrules with metal inserts are most widely used, providing the best tolerances and durability. Another critical component is the mating adaptor, and its internal sleeve that aligns the two mating ferrules.

Types of Optical Connector

There are many different fiber optic connectors. LC, FC, SC, ST are the most commonly used four connector types. All these four types of fiber optic connectors have different constructions and their respective applications. LC connector is a small form factor plastic push/pull connector with a 1.25mm ferrule. The SC connector is becoming increasingly popular in single mode fiber optic telecommunication and analog CATV, field deployed links. The high-precision, ceramic ferrule construction is optimal for aligning single mode optical fibers. The ST connector is used extensively both in the field and in indoor fiber optic LAN applications. The FC has become the connector of choice for single mode fibers and is mainly used in fiber optic instruments and high speed fiber optic communication links. Other than these four common types of connectors, there are many other kinds, such as MU, MTRJ, E2000, SMA, etc. The following picture shows the four common connector types.

four common types of connectors

Fiber Optic Connectors and Fiber Patch Cords

Fiber optic connector is an essential part of fiber patch cords. Generally, many fiber optic connectors can be manufactured for both single mode and multi-mode, simplex and duplex fiber patch cables. And fiber patch cord can have the same or different connectors at its both ends. For example, LC-LC single mode simplex fiber patch cord is a single mode simplex fiber patch cable with a simplex LC connector on each end, or SC-LC multi-mode duplex fiber patch cord is a multi-mode duplex fiber patch cable with a duplex LC connector on one end and a duplex SC connector on the other end. Fiber patch cords with various connectors are widely used in the photonics industry.

A number of events can damage fiber optic connectors. Unprotected connector ends can experience damage by impact, airborne dust particles, or excess humidity or moisture. Knowing more about optical connectors can help you select the most appropriate type and how to operate it properly to serve your network system better. Fiberstore is a professional manufacturer and supplier for optical fiber products including fiber patch cords with various connectors. One can choose the most appropriate connector type to meet his needs.

Related Article:
The Most Common Fiber Optic Patch Cables