This blog ETU -LINK will take you to read what is WDM, before that we first to get to know why the WDM technology, it appears from the background of the Internet, development rapidly in a short few decades, so operators urgently needs a lot of network capacity to meet growing customer service requirements.

For network expansion, simply increase the transmission capacity linearly by increasing the number of optical fibers, so that the transmission equipment will also increase linearly. The increase in the number of optical fibers, which need to be relaid to expand the capacity, project costs will increase exponentially. Moreover, this method does not make full use of the transmission bandwidth of optical fiber, resulting in the waste of optical fiber bandwidth resources. As the construction of communication network, it is impossible to always adopt the way of laying new optical fiber to expand the capacity. In fact, at the beginning of the project, it is difficult to predict the growing business needs and plan the number of optical fibers to be laid.

As a result, the WDM technology appears. WDM is to multiplex several or dozens of optical signals of different wavelengths into one optical fiber for transmission. The WDM technology is more common: CWDM thick WDM and DWDM dense WDM. The key technology of WDM mainly consists of three parts, which are combination/splitter, optical amplifier and light source device.

The main function of combination/splitter is to multiplex its function is to multiplex and demultiplexing various optical signals. The function of optical amplifier is to amplify the multiplexed optical signal, so as to solve the problem of long transmission distance in WDM system. We all know that the two factors affecting the transmission distance of optical communication are loss and dispersion, among which, optical amplifier solves the problem of loss, and to solve the problem of dispersion, we need to choose the semiconductor laser with very narrow spectrum to solve.

In the 10G network expansion scheme, we can use ETU-Link 10G SFP+ DWDM wavedivision optical module, which can support the transmission distance of up to 80KM. The use of DWDM dense wave division system without cable transformation, is an ideal expansion means, but also a convenient means to introduce broadband services, and the use of an additional wavelength can be introduced to any desired new services or new capacity. In addition, DWDM systems can be compatible with future all-optical networks, which may realize transparent and highly survivable all-optical networks based on the established DWDM systems in the future.