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L-band EDFA module introduction

Aug. 18, 2020
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L-band EDFA module introduction

What is the L band?

Optical fiber communication is to use light as an information carrier to transmit in the fiber core for communication. But not all light is suitable for optical fiber communication. The light wavelength is different, the transmission loss in the optical fiber is different. In order to reduce the loss as much as possible and ensure the transmission effect, scientific researchers have been working hard to find the most suitable light.

In the early 1970s, optical fiber communications started the process of practical application. At that time, the main research and development object was multimode fiber. Multimode fiber has a larger core diameter, allowing different modes of light to be transmitted on a single fiber. The first light to be used was light with a wavelength of 850nm. This band is also directly called the 850nm band. Later, in the late 1970s and early 1980s, single-mode fiber began to be widely used. After testing, it is found that the light in the wavelength range of 1260nm~16250nm has the smallest signal distortion caused by dispersion and the lowest loss. Therefore, they adopted this wavelength range as the early optical communication band and named it O-band (O-band). O means "Orignal (original)". After 30 to 40 years, after a long period of exploration and practice, a "low-loss wavelength region" was gradually summarized, that is, the 1260nm~1625nm region. Light in this wavelength range is most suitable for transmission in optical fibers. This area is further divided into five bands, namely O-band, E-band, S-band, C-band and L-band.

The wavelength of L-band light is defined as 1565nm~1625nm.

Why study L-band EDFA?

With the increase in wavelength requirements of DWDM systems, the traditional C-band can no longer meet the needs of communication systems, and it has become an inevitable development trend to extend the wavelength to the L-band or even the S-band. Because of its superior performance in the C-band, EDFA has now been widely used in optical fiber communication systems. If the working wavelength of the EDFA can be expanded from the traditional C-band to the L-band, then the advantages of EDFA can be used to obtain a wider working band at a relatively small cost.

Application of L-band EDFA

WSEE's L-band EDFA module has been widely used in high-speed optical fiber transmission systems, DWDM 10G transmission lines, and various scientific research experiments; at the same time, L-band EDFA can also be used in the field of optical fiber sensing to amplify various continuous or pulsed optical signals and improve Amplification of light energy. EDFA uses a 980nm or 1480nm pump laser to provide energy, and uses AGC, ACC or APC internal control methods. Modular products have the characteristics of small size, stability and high reliability. This product is divided into C-band, L-band and C+L-band three products, which can meet the various needs of customers. WSEE's modular EDFA is small in size and easy to integrate into the system; the company provides EDFA modules of various sizes; the module uses DC5V power input for power supply, and can communicate with the module in the form of RS232 through the host computer software, and can output optical power The parameters can be set, and the operating status of the internal parameters of the module can be read in real time.