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.

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 :


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.

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:

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