shenzhen optics forest Co.,Ltd

shenzhen optics forest Co.,Ltd

Summary of working bands of optical fiber

2023-02-21 16:23:14
 In the field of optical fiber communication, light is used as the information carrier to transmit and communicate in the fiber core. However, not all light is suitable for optical fiber communication. The transmission loss in optical fiber varies with the wavelength of light.

 In order to minimize the loss and ensure the transmission effect, scientific researchers have been working to find the most suitable light.

 850 band

  In the early 1970s, optical fiber communication started the process of practical implementation. At that time, the main research and development object was multimode fiber. The core diameter of multimode fiber is larger, allowing different modes of light to be transmitted on one fiber. The first light used is the light with a wavelength of 850 nm. This band is also directly called the 850 nm band.

 O band

  Later, in the late 1970s and early 1980s, single-mode fiber began to be widely used.

  After testing, engineers found that the signal distortion caused by dispersion is the smallest and the loss is the lowest in the wavelength range of 1260nm~1360nm. Therefore, they adopted this wavelength range as the early optical communication band and named it O-band. O. It means "Original".

   After 30 to 40 years, after a long exploration and practice, scientists gradually summarized a "low loss wavelength region", that is, 1260nm~1625nm region. The light in this wavelength range is most suitable for transmission in optical fiber. 1260nm-1625nm1260 is further divided into five bands, namely, O band, E band, S band, C band and L band.

   The wavelength range of O band is 1260nm~1360nm. The signal distortion caused by light dispersion in this band is the smallest, and the loss is the lowest, which is the early optical communication band. Therefore, it is named O-band, where O refers to "Original"


  The wavelength range of E-band is 1360nm~1460nm, and E-band is the least common of the five bands. E refers to "extended". From the above diagram of transmission loss and optical band, we can see that there is an obvious irregular transmission loss bump in E-band. This transmission loss bump is caused by the absorption of light at the wavelength of 1370nm~1410nm by hydroxide ion (OH -), which leads to a sharp increase in transmission loss. This bump is also called water peak.

 Due to the limitation of early optical fiber technology, water (OH base) impurities are often left in the optical fiber glass fiber, resulting in the highest attenuation of E-band light transmission in the optical fiber, which cannot be normally used for transmission and communication. With the improvement of optical fiber processing technology, ITU-T G.652. D optical fiber appears, which makes the transmission attenuation of E-band light lower than that of O-band light, and solves the water peak problem of E-band light. ITU-T G.652. D optical fiber is a low water peak optical fiber.


 S-band wavelength range: 1460nm~1530nm. S refers to "short wavelength". The transmission loss of S-band light is lower than that of O-band light, and it is often used for the downlink wavelength of PON (passive optical network) system.


 C-band wavelength range: 1530nm~1565nm. C means "conventional". C-band light has the lowest transmission loss and is widely used in metropolitan area networks, long-distance, ultra-long-distance and submarine optical cable systems. C-band is also often used in wavelength division networks.


L-band wavelength range: 1565nm~1625nm. L refers to "long wavelength". The transmission loss of L-band light is the second lowest. When C-band light is not enough to meet the bandwidth requirements, L-band light will be used as a supplement for optical networks.


In addition to the above five bands, there is actually another band that will be used, that is, the U band. The wavelength range of U-band is 1625 nm~1675 nm. U refers to "ultra long wavelength". U-band is mainly used for network monitoring.


Get Quote Now

Put forward your needs, we will try our best to meet them, and make customers satisfied is our eternal pursuit