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Introduction of Fiber Optic Coupler with its Benefits & Classification

by Fiber-MART.COM

A fiber optic coupler is an indispensable part of the world of electrical devices. Without these no signals would be transmitted or converted from inputs to outputs. This is the reason these are so important thereby this article discussed about these, introduction, classification and benefits in detail.
Fiber Optic Coupler is an optical cog that is capable of connecting single or multiple fiber ends in order to permit the broadcast of light waves in manifold paths. This optical device is also capable of coalescing two or more inputs into a single output while dividing a single input into two or more outputs. In comparison to a connector or a splice, the signals may be even more attenuated by FOC i.e. Fiber Optic Couplers; this is due to the division of input signal amongst the output ports.
Types of Fiber Optic Coupler
Fiber Optic Couplers are broadly classified into two, the active or passive devices. For the operation of active fiber coupler an external power source is required, conversely no power is needed when it comes to operate the passive fiber optic couplers.
Fiber Optic Couplers can be of different types for instance X couplers, PM Fiber Couplers, combiners, stars, splitters and trees etc. Let’s discuss the function of each of the type of the Fiber Optic Couplers:
Combiners: This type of Fiber Optic Coupler combines two signals and yields single output.
Splitters: These supply multiple (two) outputs by using the single optical signal. The splitters can be categorized into T couplers and Y couplers, with the former having an irregular power distribution and latter with equal power allocation.
Tree Couplers: The Tree couplers execute both the functions of combiners as well as splitters in just one device. This categorization is typically based upon the number of inputs and outputs ports. These are either single input with a multi-output or multi-input with a single output.
PM Coupler: This stands for Polarization Maintaining Fiber Coupler. It is a device which either coalesces the luminosity signals from two PM fibers into a one PM fiber, or splits the light rays from the input PM fiber into multiple output PM fibers. Its applications include PM fiber interferometers, signal monitoring in its systems, and also power sharing in polarization sensitive systems etc.
Star Coupler: The role of star coupler is to distribute power from the inputs to the outputs.
Benefits of Fiber Optical Couplers
There are several benefits of using fiber optic couplers. Such as:
Low excess loss,
High reliability,
High stability,
Dual operating window,
Low polarization dependent loss,
High directivity and Stumpy insertion loss.
The listed benefits of Fiber Optical Couplers make them ideal for many applications for instance community antenna networks, optical communication systems and fiber-to-home technology etc.

LC Fiber Connector, Adapter and Cable Assemblies

by Fiber-MART.COM

LC fiber connectors, as the most well-known representative of SFF(Small Form Factor) connector, are widely adopted in today’s LAN and data center cabling. LC connector, LC fiber adapter and cable assemblies meet the growing demand for small form factor, high-density fiber optic connectivity with simplex, duplex, single mode and multimode options. In this blog, we are going to explore the world of LC solutions.

LC Fiber Connector Types

Standard LC Connector
Standard LC connector was firstly licensed by Lucent Technologies and incorporated a push-and-latch design providing pull-proof stability in system rack mounts. Externally LC fiber connector with a retaining tab mechanism resembles a standard RJ45 telephone jack. Internally LC connector resembles a miniature version of the SC connector. LC fiber connectors use a 1.25mm ceramic (zirconia) ferrule. LC simplex and duplex connector is highly favored for single mode applications.
Besides the standard LC connectors, there are mini-LC duplex connectors, uniboot LC connectors, LC HD connectors, keyed LC connectors that are developed to meet the various application requirements.
Mini-LC Duplex Connectors
Mini-LC duplex connector has a reduced centerline pitch of 5.25mm instead of a standard LC pitch of 6.25mm. Mini-LC fiber connectors minimize the footprint and offer higher-density port mount for data center network equipment, which are perfect match for mini SFP(mSFP) optical transceivers. The black color duplex latch clips and boots in mini-LC duplex connector (seen in the below picture) are used to distinguish from standard LC duplex connectors.
LC-HD Duplex High Density Connectors
LC-HD duplex high density connectors, as the name implies, are specially designed for high-density cabling applications. Together with a flexible “pull-tab” or “push-pull tab”, LC-HD duplex connectors can be easily disengaged from densely loaded patch panels without using the special tools. Thus, in high-density fiber cabling, LC-HD duplex connectors allow users smooth and easy accessibility in tight areas and avoid fiber loss from manual operation.
LC Fiber Optic Adapters & Fiber Attenuators
Fiber optic adapters, or fiber couplers are designed to connect two optic cables together. The optical fiber adapter can be inserted into different fiber connectors types at both ends to realize the conversion between interfaces such as FC, SC, ST, LC, MTRJ, MPO and LSH. LC fiber adapter features a self-adjusting mechanism designed to accommodate patch panels of thickness between 1.55 to 1.75 mm. It is available in single mode, multimode, simplex and duplex options. LC simplex adapter connects one LC connector pair in one module space. While LC duplex adapter connects two LC connector pairs in one module space.
LC fiber attenuators is another commonly used LC-related devices. An LC optical attenuator is a passive device used to reduce the power level of an optical signal in optical network where erbium doped amplifiers are being used. There are fixed and varied fiber attenuators available in different fiber connectors types and attenuation level. LC 5dB fiber attenuator means this optical attenuator uses LC fiber connector and it can reduce the fiber power level by 5dB. For more detailed information about fiber attenuator, please visit: Guideline for Fixed Fiber Optic Attenuator

 

Understanding CWDM DWDM MUX/DEMUX

In the communications market,  Wavelength Division Multiplexing (WDM) is a technology which multiplexes a number of optical carrier signals onto a single optical fiber by using different wavelengths (i.e., colors) of laser light.

In the communications market,  Wavelength Division Multiplexing (WDM) is a technology which multiplexes a number of optical carrier signals onto a single optical fiber by using different wavelengths (i.e., colors) of laser light. This technique enables bidirectional communications over one strand of fiber, as well as multiplication of capacity.

The WDM is divided into three types (WDM, CWDM and DWDM) on the basis of wavelength difference among the three.

CWDM Mux/Demux

Dense Wavelength Division Multiplexing (CWDM) networks need multiplexer/demultiplexer (MUX/DEMUX) modules to combine and split wavelength channels at standard ITU grid. These modules are generally called CWDM MUX/DEMUX.

The CWDM Mux/Demux is a universal device capable of combining nine optical signals into a fiber pair. It is designed to support a broad range of architectures, ranging from scalable point-to-point links to two fiber-protected rings. The market-standard LGX™ packaging of the CWDM Mux/Demux enables easy deployment in existing LGX-compatible frames or WaveReady 3500F shelves.

The CWDM Mux/Demux is designed to interoperate with both the WaveReady line of transponder and optical regenerator solutions as well as CWDM transponders and small form-factor pluggables (SFPs) used in widely available transmission equipment. With billions of field operating hours, the industry leading Lumentum optical multiplexing technology offers unparalleled reliability and leading-edge performance.

CWDM Mux/Demux is a flexible network solution for WDM optical networks. At most 18 full-duplex wavelengths can be added over a single fiber trunk which greatly alleviates fiber exhaustion. With low insertion loss and high stability, CWDM Mux/Demux is applied to many operations, such as CATV links, WDM systems, test and measurement, metro and access networks, FTTH networks, etc. The deployment of CWDM Mux/Demux is transparent and clear. Its compact form factor enables a much easier manipulation. Only coarse wavelengths can be transmitted over the fiber which reduces the WDM system cost.

Three kinds of CWDM Mux/Demux are widely used in the application. They are 1RU 19″ rack chassis CWDM Mux/Demux, half 19″/1RU CWDM Mux/Demux and splice/pigtailed CWDM Mux/Demux. CWDM Mux/Demux in 19 inch rack mount package is often used for CWDM, EPON and CATV network. Half 19″/1RU CWDM Mux/Demux is packed in LGX box using thing film coating and non-flux metal bonding micro optics packaging. Splice/pigtailed CWDM Mux/Demux is packed in the ABS box package based on standard thin film filter (TFF) technology.

DWDM Mux/Demux

Dense Wavelength Division Multiplexing (DWDM) networks need multiplexer/demultiplexer (MUX/DEMUX) modules to combine and split wavelength channels at standard ITU grid. These modules are generally called DWDM MUX/DEMUX.

DWDM Mux/Demux conveys optical signals in a more dense wavelength. It is especially used for long distance transmission where wavelengths are highly-packed together. The maximum delivered wavelengths can reach up to 48 channels in 100GHz grid (0.8nm) and 96 channels in 50GHz grid (0.4nm). DWDM Mux/Demux uses a reliable passive WDM technology that achieves low insertion loss. And it provides a solution for adding WDM technology to any existing network device. Applications like point-to-point DWDM fiber optimization, linear add/drop DWDM fiber optimization, external optical monitoring are typically using DWDM Mux/Demux module.

The functionality of DWDM (Dense Wavelength Division Multiplexing) resembles to the one of CWDM. The DWDM channel spacing is 0.8/0.4 nm (100 GHz/50 GHz grid). This small channel spacing allows to transmit simultaneously more information. Currently a restriction on wavelengths between 1530 nm and 1625 nm exists which corresponds to the C and L band. DWDM wavelengths are more expensive compared to CWDM caused by the need of more sophisticated transceivers.

Likewise, 1RU 19″ rack chassis DWDM Mux/Demux, Half 19″/1RU DWDM Mux/Demux and splice/pigtailed DWDM Mux/Demux are three divisions of DWDM Mux/Demux modules. The first type is in 19 inch rack mount package used for long-haul transmission over C-band range of wavelengths. The second one is in LGX package used for PDH, SDH/SONET, Ethernet services transmission. The last one is in ABS box package and its pigtails are labeled with wavelengths.

Comparison Between CWDM and DWDM System

The difference between CWDM and DWDM lies in the channel spacing between neighbored wavelengths, for CWDM 20 nm and for DWDM 0.8/0.4 nm (using 100 GHz/50 GHz grid). this advantage for an efficient CWDM/DWDMintegration. Thereby up to sixteen DWDM channels are transmitted simultaneously in only one CWDM channel (1530 nm and 1550 nm). Thus an easy-to-realize channel extension can be achieved under continued use of existing CWDM components.

Price difference—CWDM system carries less data, but the cabling used to run is less expensive and less complex. A DWDM system has much denser cabling and can carry a significantly larger amount of data, but it can be cost prohibitive, especially where there is a need for a large amount of cabling in an application.

Transmission distance—DWDM system is designed for longer distance transmission as stated above. They can transmit more data over a significantly larger run of cable with less interference than a comparable CWDM system. If there is a need for transmitting the data over a long range, DWDM system will likely be the best in terms of functionality of the data transmittal and the lessened interference over the longer distances that the wavelengths must travel.

CWDM system cannot transmit over long distances because the wavelengths are not amplified, and therefore CWDM is limited in its functionality over longer distances. Typically, CWDM can travel anywhere up to about 100 miles (160 km), while an amplified DWDM system can go much further as the signal strength is boosted periodically throughout the run. As a result of the additional cost required to provide signal amplification, the CWDM solution is best for short runs that do not have mission critical data.

To sum up, before buying We should first understand the differences between them,Fiber-Mart provides a series of CWDM DWDM MUX/DEMUX modules with as more as 18 channels (20nm spaced) in simplex or duplex configurations. All the CWDM  DWDM modules are available with three types of packaging: ABS Pigtailed Box, Rack Chassis and LGX Cassette. For more details, please visit www.fiber-mart.com. Please not hesitate to contact us for any question. E-mail: service@fiber-mart.com

Why on earth do we need to choose active optical cable(AOC)?

AOCs bond the fiber connection inside the transceiver end, creating a complete cable assembly much like a DAC cable, only with a 3-200-meter reach capability.

What is an AOC? 

—Here is the brief definition of AOC:

Optical transceivers convert electrical data signals into blinking laser light which is then transmitted over an optical fiber. Optical transceivers have an optical connector to disconnect the fiber from the transceiver. AOCs bond the fiber connection inside the transceiver end, creating a complete cable assembly much like a DAC cable, only with a 3-200-meter reach capability. AOCs main benefit is the very long reach of optical technology, while acting like a simple, “plug & play” copper cable.Active Optical Cable assemblies have been designed to support multiple protocols. Most of them are compliant with SFP+ Ethernet and InfiniBand electrical. Here is what a typical 40 Gb/s QSFP+ (Quad Small Form-Factor Pluggable Plus) AOC supports.

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Mainly, active optical cable (AOC) assemblies were invented to replace copper technology in data centers and high performance computing (HPC) applications. As we know, copper passive twinax cable is heavy and bulky, making it difficult to physically manage the datacenter. And due to the nature of electrical signals, electromagnetic interference (EMI) limits copper’s performance and reliability. Though there are so many disadvantages of copper cable, at that time, it is the main stream while the idea of AOC cables almost seems too good to be true. However, the advantages of AOC cables make the predecessors look obsolete and unsophisticated, and changes the limitation of copper passive twinax cable as well as playing an important role in high speed data transmission. Nowadays, a variety of active optical cable have been launched in the market, such as 10G SFP+ AOC, 40G QSFP+ to QSFP+ AOC,40G QSFP+ to 4 SFP+ breakout AOC ,40G QSFP+ to 8xLC breakout AOCs.

What are AOC Features and Advantages?

Compared to less expensive DAC cables, AOC offer:

  • Longer reach capability than DAC 3-7 meter limits;
  • 3m – 100-meters multi-mode technology;
  • 100-200 meters with single-mode, Silicon Photonics;
  • Lower weight, thinner cable and bend radius enabling increased airflow cooling and easier system maintenance.

Compared to more expensive optical transceivers, AOC offer:

  • Dramatically lower priced solution than two optical transceivers and connectorized fiber based links;
  • Lower power consumption at 2.2 Watts versus up to 4.5 Watts for optical transceivers (4-channel);
  • Lower operational and maintenance cost.

 

Fiber-Mart supplies various kinds of high speed interconnect AOC cable assemblies including 10G SFP+ AOC, 40G QSFP+ AOC Cables,100G QSFP28 AOC, 120G CXP AOC Cables. For more information, you can visit web Fiber-MART.COM.if you have something interest, pls feel free to contact us：service@fiber-mart.com

The introduction to EDFA(Erbium-Doped Fiber Amplifier)

EDFA is an optical repeater device that is used to boost the intensity of optical signals being carried through a fiber optic communications system.It was invented in 1987, EDFA exhibits its gain in the C-band and L-band

EDFA is an optical repeater device that is used to boost the intensity of optical signals being carried through a fiber optic communications system.It was invented in 1987, EDFA exhibits its gain in the C-band and L-band, where telecomputer optical fibers show its lowest loss in the entire optical telecommunication wavelength bands.

What does Erbium-Doped Fiber Amplifier (EDFA) mean?

EDFAs are used as a booster, inline, and pre-amplifier in an optical transmission line, as schematically shown in Figure 1. The booster amplifier is placed just after the transmitter to increase the optical power launched to the transmission line. The inline amplifiers are placed in the transmission line, compensating the attenuation induced by the optical fiber. The pre-amplifier is placed just before the receiver, such that sufficient optical power is launched to the receiver.

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Figure 1

It is used in the telecommunications field and in various types of research fields .An EDFA is “doped” with a material called erbium. The term “doping” refers to the process of using chemical elements to facilitate results through the manipulation of electrons.

How it Works

An optical fiber is doped with the rare earth element erbium so that the glass fiber can absorb light at one frequency and emit light at another frequency. An external semiconductor laser couples light into the fiber at infrared wavelengths of either 980 or 1480 nanometers. This action excites the erbium atoms. Additional optical signals at wavelengths between 1530 and 1620 nanometers enter the fiber and stimulate the excited erbium atoms to emit photons at the same wavelength as the incoming signal. This action amplifies a weak optical signal to a higher power, effecting a boost in the signal strength.

Before the invention of EDFA, a long optical fiber transmission line required a complicated optical-to-electrical (O-E) and E-O converter for signal regeneration. The use of EDFA has eliminated the need for such O-E and E-O conversion, significantly simplifying the system. This is especially of use in a submarine optical transmission, where more than a hundred repeaters may be needed to construct one link. The TPC-5CN (Trans-Pacific Cable 5 Cable Network), started its operation in 1996, is the first submarine optical fiber network which employed EDFA.

The EDFA rate, or amplification window, is based on the optical wavelength range of amplification and is determined by the dopant ions’ spectroscopic properties, the optical fiber glass structure and the pump laser wavelength and power. As ions are sent into the optical fiber glass, energy levels broaden, which results in amplification window broadening and a light spectrum with a broad gain bandwidth of fiber optic amplifiers used for wavelength division multiplex communications. This single amplifier may be used with all optic fiber channel signals when signal wavelengths are in the amplification window. Optical isolator devices are placed on either side of the EDFA and serve as diodes, which prevent signals from traveling in more than one direction.

EDFAs are usually limited to no more than 10 spans covering a maximum distance of approximately 800 kilometers (km). Longer distances require an intermediate line repeater to retime and reshape the signal and filter accumulated noise from various light dispersion forms from bends in the optical fiber. In addition, EDFAs cannot amplify wavelengths shorter than 1525 nanometers (nm).

Fiber-MART Optical Amplifier & EDFA

Optical Amplifiers provided by Fiber-Mart are designed for all network segments (access, metro, regional and long haul) and applications (telecom, cable and enterprise). We have a series of Erbium-Doped Fiber Amplifier (EDFA) optical amplifiers, including DWDM EDFA for DWDM systems, CATV EDFA for CATV applications, SDH EDFA for SDH networks. In addition, we can also provide Raman Fiber Amplifiers, DCM EDFA with mid-stage access, and high power amplifiers such as EYDFA.

In a word , Optical Amplifier & EDFA enables the optical transmission over long distance by amplifying signals. For more information, please visit Fiber-MART.COM .pls not hesitate to contact us for any requirements : service@fiber-mart.com

 

Optical Amplifier & EDFA
Optical Amplifier & EDFA

Fiber Optic Transceiver

SFP modules allows for an optical or electrical interface when using a managed switch, unmanaged switch or media converter. These interchangeable SFP modules are available for use with copper media, multimode optical fiber

With the economic development, the communication technologies are increasingly applied to all walks of life.

Let’s talk about SFP Transceiver-—Data can usually travel only one way in a fiber optic cable, so most transceivers have two ports for bidirectional communication: one for sending and the other for receiving signals. Alternatively, a single cable can be used, but it can only send or receive data at a time but not both. The opposite end of the transceiver has a special connector for fitting it into specific models of enterprise-grade Ethernet switches, firewalls, routers and network interface cards. A modern fiber optic transceiver is a small device because it is intended to plug into the aforementioned network devices; this type of transceiver is called a small form-factor pluggable transceiver.

 SFP modules allows for an optical or electrical interface when using a managed switch, unmanaged switch or media converter. These interchangeable SFP modules are available for use with copper media, multimode optical fiber, or single mode optical fiber. The optical fiber SFP modules are available in Fast Ethernet one and two fiber versions and Gigabit Ethernet one and two fiber versions.

Transceivers include transmission and receiver in a single module. The transmitter takes an electrical input and converts it to an optical output from a laser diode or LED. The light from the transmitter is coupled into the fiber with a connector and is transmitted through the fiber optic cable plant. The light from the end of the fiber is coupled to a receiver where a detector converts the light into an electrical signal which is then conditioned properly for use by the receiving equipment. And this is conversion from electricity to light, light to electricity.

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They also are available with LC or SC optical connectors.A fiber optic transceiver is a device that uses fiber optical technology to send and receive data. The transceiver has electronic components to condition and encode/decode data into light pulses and then send them to the other end as electrical signals. To send data as light, it makes use of a light source, which is controlled by the electronic parts, and to receive light pulses, it makes use of a photo diode semiconductor.

As with most devices, there are many kinds and models of transceivers available, which range in size, performance and price.

Transmitting Rates and Range—Both the single-mode and multi-mode fiber optic transceiver can handle the 10G speeds. However, distance requirements are quite critical. The multi-mode optical transceivers generally have a reach of approximately 550 meters, while the single-mode transceivers can get you through 10 km, 40 km, 80 km and even farther.

Price—The optics used in the single-mode fiber are twice those used in the multimode fiber. But when installed as part of a project, the extra cost of single-mode fiber is negligible compared to multimode fiber. The fragility and increased cost to produce single-mode fiber makes it more expensive to use.

Compatibility—When it comes to issues dealing with compatibility, the two types of transceivers are not compatible. You cannot mix the multi-mode and the single-mode fiber between any two endpoints.

Power Dissipation—Multimode transceivers consume less power than single-mode transceivers, which is an important consideration especially when assessing the cost of powering and cooling a data center.

 Fiber-MART is is a leading communication systems technologies integrator and optical solutions provider. We are dedicated to helping you build, connect, protect and optimize your optical infrastructure.pls feel free to contact with us for any question. e-mail: service@fiber-mart.com

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