Analysis of WDM optical division multiplexing technology

This article will introduce WDM optical division technology, WDM is a technology that transmits multi-wavelength optical signals simultaneously in a fiber. Multiplexing for short, WDM, also known as Wavelength Division Multiplexing. Compared with single wavelength technology, WDM WDM technology can save more fiber resources. Its basic principle is to use the wavelength division multiplexer (wave synthesizer) at the transmitter end to combine the information optical carriers of different wavelengths into a fiber for transmission, and at the receiver end, another wavelength division multiplexer (wave splitter) to separate the different optical carriers.

WDM technology is mainly used to expand the optical fiber communication system. It can transmit signals of several channels simultaneously using optical carriers of different wavelengths in one optical fiber. WDM systems all operate in the 1550nm window. Quartz fiber in 1550 wavelength region has three bands can be used, namely S band, C band and L band. Among them, the wavelength range of S-band is 1460 ~ 1530nm, the wavelength range of C-band is 1530 ~ 1565nm, and the wavelength range of L-band is 1570 ~ 1605nm.

Wavelength division multiplexing (WDM) with 1310nm/1550nm Windows is used in access networks but is rarely used for long-distance transmission. Dense wavelength division multiplexing (DWDM) with 1550nm window: It can be widely used for long-distance transmission and construction of all-optical networks. Because 1310/1550nm multiplexing is beyond the gain range of EDFA, it is only used in some specialized applications, so the more generalized name WDM is often used instead of DWDM. At present, 1.25G DWDM and 10G DWDM optical modules are used for long-distance transmission in the backbone network.

WDM technology can make full use of the huge bandwidth resources of optical fiber. In a single optical fiber, the transmission capacity of WDM is several times, tens of times, hundreds of times of a single wavelength. In addition, WDM technology signals transparent transmission, the channel of each wavelength is independent of each other, can transmit signals with completely different characteristics and rates, complete the comprehensive transmission of various telecommunications signals, such as PDH signal and SDH signal, digital signal and analog signal, a variety of services (audio, video, data, etc.) mixed transmission.