An Alternative Reading of Fiber Optic Connector

Being a part of the fiber patch cable, the fiber optic connector is utilized to achieve accurate and precise connections of the fiber ends. Now there are many kinds of fiber optic connectors in the market, such as ST, FC, SC, LC and so on (as shown in the following figure). Since the fiber cable transmits pulses of light instead of electrical signals, it is important to choose a good fiber optic connector that aligns microscopic glass fibers perfectly in order to allow for communication. This post will introduce fiber optic connector in an alternative way.

Structure of Fiber Optic Connector

Though the mechanical design varies a lot among different connector types, the most common elements in a fiber connector can be similar. That’s to say, the connector is mainly composed of fiber ferrule, connector sub-assembly body, connector housing, fiber cable and stress relief boot. The following figure takes SC connector as example to show the general components of the connectors.

Typical Types of Fiber Optic Connector

Different kinds of optical fiber cables may need different connectors. Seen from the types of optical fiber, the fiber optic connectors may be loosely classified into standard fiber optic connectors, small form factor fiber optic connectors and ribbon fiber connectors. These family types of fiber connectors sometimes may overlap with each other.

Standard Fiber Optic Connectors

Generally having a ferrule of 2.5mm, standard fiber optic connectors are connectors commonly used in the fiber network. They can be both simplex and duplex and available in single mode and multi-mode fibers. ST, FC, SC, FDDI and ESCON are all standard fiber connectors. But they also differ from each other. ST connector is the most popular connector for multi-mode fiber optic LAN applications. FC connector is specifically designed for telecommunication applications and provides non-optical disconnect performance. SC connector is widely used in single mode applications for its excellent performance. FDDI connector, which is a duplex multi-mode connector, utilizes two 2.5mm ferrules and is designed to used in FDDI network. ESCON connectors are similar to FDDI connectors, but contain a retractable shroud instead of a fixed shroud.

Small Form Factor Fiber Optic Connectors

To meet the demand for devices that can fit into tight spaces and allow denser packing of connections, a number of small form factor fiber optic connectors have been developed since the 1990s. In this type of small form factor fiber optic connectors, some are miniaturized versions of older connectors, built around a 1.25mm ferrule rather than the 2.5mm ferrule. For example, the LC, MU, E2000 connectors. While the others are based on smaller versions of MT-type ferrule for multi-mode fiber connections, or other brand new designs. For example, the MT-RJ connector, which has a miniature two-fiber ferrule with two guide pins parallel to the fibers on the outside. Its overall size is about the same as a RJ45 connector.

Ribbon Fiber Connectors

MTP and MPO are compatible ribbon fiber connectors based on MT ferrules which allow quick and reliable connections for up to 12 fibers. Since the MTP product complies with the MPO standard, the MTP connector is an MPO connector. Along with the MTP patch cables (for example, MTP-MTP fiber trunk cable), MTP connectors can upgrade the 10G network to 40G/100G.

Conclusion

The fiber optic connector is an essential part in fiber optical network. As the popularity of fiber optical network, about 100 fiber optic connectors have been introduced to the market. FS.COM is the main professional fiber optic products supplier in China, and we offers various kinds of fiber cable connectors, especially the commonly used FC, LC, SC, ST and MPO connectors.

Originally published at www.fiber-optic-cable-sale.com.

Important Components for 40/100G Ethernet Migration

With the growth of bandwidth-intensive applications such as high-performance computing and business continuity, there emerge higher-speed networks of 40/100G Ethernet. And as products become less expensive and more available over time, 40/100G Ethernet will inevitably be commonplace in our daily life. Therefore, it is necessary to create a migration path by installing a structured cabling system that can support the future 40/100G networking needs. In this system, such fiber optic products as MTP/MPO connectors, 40/100G transceivers and 40/100G direct attach cables (DACs) are important components. This article will discuss their roles in 40/100G Ethernet migration respectively.

MTP/MPO Connectors

Since 40/100G Ethernet uses parallel optics technology which requires data transmission across multiple fibers simultaneously, the multi-fiber connectors are needed. MTP/MPO is the designated interface for multi-mode 40/100G Ethernet, and its backward is compatible with legacy 1G/10G applications as well. 40G Ethernet uses a 12 position MTP/MPO connector interface that aligns 12 fibers in a single row. And the 4 leftmost fibers are used to transmit data, the middle 4 fibers are left unused, while the 4 rightmost fibers are used to receive data. 100G Ethernet uses a 24 position MTP/MPO connector with two rows of 12 fibers. And the outermost fibers on either end of the rows are vacant, while 10 fibers in the upper row for transmitting data and the remaining 10 fibers in the lower row for receiving data.

40/100G Transceivers

Together with MTP/MPO connectors, 40/100G transceivers are often used (as shown in the above figure). Through the use of plug-and-play, hot-swap transceiver miniaturization, fiber connectivity in higher-speed active equipment is being condensed and simplified. Transceivers used in 40/100G Ethernet migration include 40G QSFP+ transceivers, 100G CFP transceivers and so on. 40G QSFP+ transceivers can support 4x10G modes, which allow new parallel optics active equipment being compatible with existing 10G transceivers. And the electrical connection of a 100G CFP transceiver uses 10x10G lanes in RX (receive) and TX (transmit) direction, supporting both 10x10G and 4x25G variants of 100G interconnects.

40/100G DACs

To save cost, 40/100G DACs are often used in 40/100G Ethernet instead of optical transceivers. Applied to short reach applications, it is a fixed assembly supporting high speed data that uses a small form-factor connector module as an optical transceiver on each end of a length of cable. The modules on each end meet small form-factor standards and have some function of the optical transceivers, meaning that DAC inherits some advantages of the small form-factor module. Thus, sometime there is no need to upgrade the equipment by using a DAC.

To meet the future 40/100G networking needs, the cabling system shall include components that not only support future high-bandwidth applications but also be compliant to 1G and 10G applications and all current and anticipated industry standards. Meeting all these requirements, the above mentioned MTP/MPO connectors, 40/100G transceivers and 40/100G DACs play important roles in migration to 40/100G Ethernet. As a professional supplier of fiber connectivity network solutions, Fiberstore supplies all these fiber optic products and other kinds of products for 40/100G Ethernet migration.

Originally published at www.fiber-optical-networking.com.

Optical Fiber Access Modes

Optical fiber broadband is a technology that converts electrical signals carrying data to optical signals and sends the optical signals through transparent glass fibers. The signal conversion process is completed through the optical modems installed on both ends of the optical fiber. Among various transmission media for the broadband network, optical fiber is an ideal one, which features in large transmission capacity, high transmission quality, long repeater spacing and low loss.

Optical fiber access technology provides users with high-speed bandwidth of 10 Mbps, 100 Mbps and 1000 Mbps that can be directly connected with the main crunodes of the internet. With high speed access to local area network (LAN) and high speed interconnection with internet, optical fiber access technology is applied mainly to LANs for business groups and intelligent residences. This article will introduce five common access modes of optical fiber.

Optical fiber + Ethernet Access

Ethernet is a kind of technology for LANs and metropolitan area networks (MANs). When the optical fiber is connected with Ethernet, it is necessary to use switch, photoelectric converter and Cat5e.

Applications: residential areas and commercial buildings where generic cabling and system integration for optical fiber access are completed or easy to be implemented.

Optical Fiber + HomePNA Access

HomePNA is an industry standard for home networking over the existing coaxial cables and telephone wiring within homes. To connected optical fiber with the HomePNA, HomePNA switch (Hub) and HomePNA termination equipment (Modem) are important to connect optical fiber to the HomePNA.

Applications: residential areas and hotel buildings where generic cabling and system integration are undone or inconvenient to be done.

Optical Fiber + VDSL Access

Very-high-bit-rate digital subscriber loop (VDSL) is a technology providing data transmission over a single flat untwisted or twisted pair of copper wires and on coaxial cable. VDSL switch and VDSL termination equipment are essential to connect optical fiber with VDSL.

Applications: residential areas and hotel buildings where generic cabling and system integration are undone or inconvenient to be done.

FTTx + LAN Access

FTTx stands for fiber to the x, where x stands for home, curb, neighborhood, business, etc (as shown in the following figure). LAN refers to local area network. FTTx+LAN access aims at Gigabit Ethernet for the community, fast Ethernet for the building and 10 Mpbs Ethernet for the user.

Applications: it is mainly applied to concentrated residential areas, enterprises and public institutions and universities and colleges. In FTTx+LAN, generic cabling is done in residential areas, high-class offices and student dormitories and teacher dormitories in universities and colleges.

Optical Fiber Access

Optical fiber access with transmission bandwidth from 2 Mbps to 155 Mbps is designed for enterprises and public institutions or groups who need the independent optical fiber-optic high-speed Internet. Since the bandwidth for upload and download is high, optical fiber access is suitable for such activities as remote instruction, tele-medicine and video conference.

Applications: it is applied to concentrated residential areas, communities and offices where generic cabling is done or easy to be implemented. Furthermore, it also applied to enterprises and public institutions or groups who need the independent optical fiber-optic high-speed Internet.

Optical fiber access is expanding due to the demand for broadband in consumer environment. Thus, products such as switches, photoelectric converters and transceivers used in optical fiber access are various in the market. As a professional supplier of optical communication products, Fiberstore supplies many kinds of products used in optical fiber access. Customers may choose the proper optical fiber optic access mode and optical fiber products according to their needs.

Originally published at www.fiber-optical-networking.com/.

Technologies Used in Multiplexing

Sending email is a commonplace occurrence in our daily life. When you send an email to a friend in another city, it will firstly join up with other messages being transmitted in your city, and then get dropped off at the correct destination in the correct city. How do all of these messages get to join together and be transmitted without getting mixed up? This process is achieved through the use of multiplmexing technology, which is a method that combines multiple analog message signals or digital data streams into one signal over a shared medium. Actually, multiplexing is widely used in many telecommunications applications. This article will introduce multiplexing technology from the aspect of common technologies used in multiplexing.

Optical multiplexing filter is an essential component in multiplexing technology, which is a physical device that combines each wavelength with other wavelengths (as shown in the following figure). Many technologies are applied in multiplexing, including thin-film filter (TFF), fiber bragg grating (FBG), arrayed waveguide grating (AWG) and interleaver, periodic filter, and frequency slicer.

TFF

Optical TFF typically consists of multiple alternating layers of high- and low-refractive-index material deposited on a glass or polymer substrate. This substrate is made to let only photons of a specific wavelength pass through, while all others are reflected.

FBG

A bragg grating is made of a small section of fiber that has been modified by exposure to ultraviolet radiation to create periodic variations in the refractive index of the fiber. And the process of creating periodic variations will generate wavelength-specific dielectric mirrors. Thus, the FBG can reflect particular wavelengths of light and transmit all others.

AWG

AWG devices can multiplex a large number of wavelengths into a single optical fiber. These devices are designed on the fundamental principle of optics that light waves of different wavelengths interfere linearly with each other. That’ to say, if each channel in an optical communication network makes use of light of a slightly different wavelength, then the light from a large number of these channels can be carried by a single optical fiber.

Interleaver, Periodic filter, and Frequency Slicer

Interleaver, periodic filter and frequency slicer are often used together to perform the function of multiplexing. The following figure shows how interleaver, periodic filter and frequency slicer work together to make a multiplexer device. Periodic filter is in stage 1, which is an AWG. Stage 2 represents the frequency slicer which is another AWG. The interleaver is at the output part, which is provided by six bragg gratings. Six wavelengths (λ) are received at stage 1 which breaks the wavelengths down into odd and even wavelengths. Then the odd and even wavelengths go to stage 2 respectively. Finally, they are delivered by the interleaver in the form of six discrete, interference-free optical channels.

All in all, the usual goal of multiplexing is to enable signals to be transmitted more efficiently over a given communication channel rather than save bandwidth. Nowadays, the most popular multiplexing technology is wavelength division multiplex (WDM), which can be divided into coarse wavelength division multiplexing (CWDM) and dense wavelength division multiplexing (DWDM). It is hoped that multiplexing technology would offer significant gains in bandwidth efficiency.

Originally published at www.fiber-optical-networking.com/

Things You Need to Know About MTP/MPO Harness Cable

A MTP/MPO harness cable, also called MTP/MPO breakout cable or MTP/MPO fan-out cable, is a fiber optic cable terminated with MTP/MPO connectors on one end and MTP/MPO/LC/FC/SC/ST/MTRJ connectors (generally MTP to LC) on the other end (as shown in the following figure). In addition to its definition, here are something you also need to know about MTP/MPO harness cable.

What Is MTP/MPO Connector

As a kind of multi-fiber connector, the MTP/MPO connector is most commonly used for 12 or 24 fibers in a single connector pushing up to and beyond 100Gbps data transmission. Thus it satisfies the huge demand for more bandwidth and more space efficiency of data centers and ever-expanding server clusters. MTP/MPO connectors are paving the way for increased data transmission speeds and rack density.

Though MTP and MPO are literally different from each other, they are often used interchangeably. The MPO connector is a multi-fiber connector that is defined by IEC-61754-7, and the MTP is a registered trade mark of US Conec (a leader in providing passive components for high density optical interconnects), which identifies a specific brand of the MPO style connector.

Common Types of MTP/MPO Harness Cable

As mentioned above, the connectors on each end of the fiber cable may be the same or not. Thus, the MTP/MPO harness cable is usually divided into MPO/MTP-MPO/MTP harness cable, MPO/MTP-Secure Keyed LC harness cable and MPO/MTP-Standard LC/FC/SC/ST/MTRJ harness cable. In the MPO/MTP-Secure Keyed LC harness cable, the secure keyed LC connector provides a quick, simple termination method, featuring a pre-installed cleaved fiber with an index-matching splice element, and a precision factory pre-polished zirconia ceramic ferrule.

Differences Between MTP/MPO Harness Cable and MTP/MPO Trunk Cable

MTP/MPO harness cables and MTP/MPO trunk cables are two common kinds of MTP/MPO fiber cables. They differ from each other in such aspects as function and application.

MTP/MPO harness cables are designed for high density applications requiring high performance and speedy installation. Harness cables provide a transition from multi-fiber cables to individual fibers or duplex connectors. Therefore, they can meet a variety of fiber cabling requirements.

MTP/MPO trunk cables are designed for high density applications which offer excellent benefits in terms of on-site installation time and space saving. Trunk cables serve as a permanent link connecting the MTP/MPO modules to each other.

MTP/MPO harness Cable in 40GbE/100GbE Migration

As data communication technology migrates from 10GbE to 40GbE and 100GbE, transition from discrete commercial connectors to MTP/MPO connectors is essential. MTP/MPO harness cables are ideal for connecting high speed switches populated with such higher rate transceivers as QSFP+ transceivers to existing 10GbE elements populated with SFP+ modules.

Conclusion

Generally speaking, with its high-density MTP/MPO connectors and harness cables, the MTP/MPO harness cable is suit for high density environment that demands space saving and reduced cable management solutions. Furthermore, supporting various connections from multi-fiber to single-fiber, the MTP/MPO harness cable is an ideal connection to patch panels and data distribution routing.

Originally published at www.fiber-optical-networking.com/

Important Components in DWDM System

Dense wavelength division multiplexing (DWDM) is one of the most recent and important technologies in the development of fiber optic transmission technology. Its most obvious advantage is the ability to provide potentially unlimited transmission capacity. In a DWDM system, there are four important components, which are optical transmitter/receiver, DWDM Mux/Demux filter, optical add/drop multiplexer (OADM) and optical amplifier. This article will give an introduction to these four components respectively.

Optical Transmitter/Receiver (Transceiver)

As a highly important part in the DWDM system, the optical transmitter/receiver is responsible for providing source signals and receiving signals. Multiple optical transmitters are used as the light sources in a DWDM system. The lasers on the transmit side create pulses of light. Each light pulse has an exact wavelength which shall be precise and stable.

As the development of fiber optic transmission technology, the optical transmitter/receiver has been gradually replaced by the optical transceiver. Optical transceiver is a device comprising both a transmitter and a receiver which are combined and share common circuitry or a single housing. There is another device named transponder used in the DWDM system sometimes. It has the similar principle with the optical transceiver. Both optical transceivers and transponders have the function of optical-electrical-optical (O-E-O) conversion. The main difference between them is that the interface of optical transceivers is serial, while the interface of transponders is parallel.

DWDM Mux/Demux Filters

It is known to us that multiple wavelengths created by multiple transmitters operates on different fibers. The role of optical filter (multiplexer filter) is to combine these multiple wavelengths onto one fiber. The output signal of an optical multiplexer is referred to as a composite signal. Then an optical drop filter (demultiplexer) at the receiving end performs the function of separating out all the individual wavelengths of the composite signal to individual fibers. One thing needed to be noted is that the demultiplexing process should be done before the light is detected. The following figure shows a bidirectional DWDM operation. N light pulses of N different wavelengths carried by N different fibers are combined by a DWDM Mux. A DWDM Demux receives the composite signal and separates each of the N component signals and passes each to a fiber.

DWDM OADM

In the DWDM system, there is an area in which multiple wavelengths exist between multiplexing and demultiplexing points. And it is desirable that one or more wavelengths at some point along this span can be added or dropped. The OADM is designed for this function. Rather than combining or separating all wavelengths, the OADM can remove some of the wavelengths and allow the other wavelengths to pass on. The following figure shows the add-drop process of OADM ("Amp" represents for amplification, "λ" represents for wavelength).

Optical Amplifier

Since the DWDM system is for long transmission links, the signals must be amplified after a certain fiber length. As a kind of “in-fiber” device, optical amplifier boosts the amplitude or add gain to optical signals passing on a fiber through the way of directly stimulating the photons of the signal with extra energy. Optical amplifier can amplify optical signals across a broad range of wavelengths, which is very important for DWDM system application. The commonly used in-fiber amplifier is erbium-doped fiber amplifier (EDFA).

Continuing to provide the bandwidth for large amounts of data, DWDM is now becoming the basis of all-optical networking with wavelength provisioning and mesh-based protection.

Originally published at www.fiber-optical-networking.com/.

1000BASE SFP Transceivers Used in Gigabit Ethernet

Gigabit Ethernet, which is standardized by the IEEE as the 802.3z standard, is a term describing various technologies for transmitting Ethernet frames at a rate of a Gigabit per second. The 1000BASE SFP transceiver is an important part in Gigabit Ethernet applications, which is a hot-swappable input/output device that plugs into a Gigabit Ethernet port/slot, linking the port with the network. There is a number of 1000BASE SFP transceivers that are available in accordance with the customer application and distance capability required.

Depending on the cable material, Gigabit Ethernet can be classified into fiber-based Gigabit Ethernet and copper-based Gigabit Ethernet. Different 1000BASE SFP transceivers may used in different kinds Gigabit Ethernet.

1000BASE SFP Transceivers in Fiber-based Gigabit Ethernet

In fiber-based Gigabit Ethernet, 1000BASE-X is used in industry to refer to Gigabit Ethernet transmission over fiber. 1000BASE-X is a group of standards for Ethernet physical layer standards, including 1000BASE-SX, 1000BASE-LX, 1000BASE-LX10, 1000BASE-BX10 or the non-standard 1000BASE-EX and 1000BASE-ZX implementations. Different 1000BASE SFP transceivers may be used in different standards.

• 1000BASE-SX SFP Transceiver for 1000BASE-SX

1000BASE-SX operates over multi-mode fiber using an 850nm laser. 1000BASE-SX SFP transceiver is a high performance module used for 1000BASE-SX. It operates on legacy multi-mode fiber links up to 550m and on Fiber Distributed Data Interface (FDDI)-grade multi-mode fibers up to 220m, supporting up to 1km over laser-optimized multi-mode fiber cable.

• 1000BASE SFP Transceiver for 1000BASE-LX

1000BASE-LX represents the long wave laser version of Gigabit Ethernet over fiber, which can operate over single-mode or multi-mode fiber. The 1000BASE-LX SFP transceiver operates on standard single-mode fiber-optic link spans of up to 10km and up to 550m on any multi-mode fibers.

• 1000BASE SFP Transceiver for 1000BASE-LX10

1000BASE-LX10 is very similar to 1000BASE-LX, but it achieves longer distances over a pair of single-mode fiber. The 1000BASE-LX10 SFP transceiver can operate over single-mode fiber links up to 10km.

• 1000BASE SFP Transceiver for 1000BASE-BX10

1000BASE-BX10 is capable of up to 10 km over a single strand of single-mode fiber. The 1000BASE-BX10 SFP Transceivers operate on a single strand of standard single-mode fiber.

• 1000BASE SFP Transceiver for 1000BASE-EX

1000BASE-EX a industry accepted term to refer to Gigabit Ethernet transmission. The 1000BASE-EX SFP transceivers operate on standard single-mode fiber-optic link spans of up to 40 km in length.

• 1000BASE SFP Transceiver for 1000BASE-ZX

Through the use of single-mode fiber and a long-wavelength laser (1550nm), 1000BASE-ZX obtains a span line of 70km. Operating on standard single-mode fiber-optic link spans of up to approximately 70km in length, the 1000BASE-ZX SFP transceivers are used in long-reach single-mode fibers.

1000BASE SFP Transceivers in Copper-based Gigabit Ethernet

In copper-based Gigabit Ethernet, 1000BASE-CX, 1000BASE-KX, 1000BASE-T and 1000BASE-TX are four standards for Gigabit Ethernet over copper wiring. Similarly, various 1000BASE SFP transceivers are used in these four standard.

• 1000BASE SFP Transceiver for 1000BASE-CX

1000BASE-CX represents the initial IEEE standard for Gigabit Ethernet over copper cabling using 150Ω balanced shielded twisted-pair wire. The 1000BASE-CX SFP transceiver is intended for short cable runs over copper cabling.

• 1000BASE SFP Transceiver for 1000BASE-KX

1000BASE-KX is part of the IEEE 802.3ap standard for Ethernet Operation over Electrical Backplanes. Since it uses electrical signaling speed rather than optical signaling, there is no SFP Transceiver for this standard.

• 1000BASE SFP Transceiver for 1000BASE-T

1000BASE-T defines the transmission of Gigabit Ethernet over four pairs of cable. The 1000BASE-T SFP transceiver operates on standard Category 5 unshielded twisted-pair copper cabling of link lengths up to 100m.

• 1000BASE SFP Transceiver for 1000BASE-TX

1000BASE-TX is similar to 1000BASE-T but uses two pairs of wires rather than four for data transmission. Theoretically, it is design to reduce the cost of the required electronics by only using two unidirectional pairs in each direction instead of 4 bidirectional. But this is proved to be a commercial failure. Therefore, 1000BASE-TX SFP Transceiver is uncommon.

As Gigabit Ethernet has been demonstrated to be a viable solution for increased bandwidth requirements for growing networks, the market is flooded with various 1000BASE SFP transceivers. Fiberstore supplies many kinds of 1000BASE SFP transceivers including the aforesaid 1000BASE-SX SFP, 1000BASE-LX SFP, 1000BASE-ZX SFP, 1000BASE-LH SFP and 1000BASE-T SFP transceivers and so on.