The International Telecommunication Union (ITU) has published a new technical report. It can form the basis for the development of a roadmap to establish standards for space distribution multiplexing (SDM) in the transmission of signals in fiber-optic cables of broadband networks. This, in turn, will increase the capacity of future communication channels for transmitting big data, explains ISPreview.
Most fiber optic cables typically support Wavelength Multiplexing (WDM) technology. In simple terms, this technology simultaneously combines (multiplexes) several optical signals into one fiber optic cable, transmitting them using laser beams of different colors (i.e., different wavelengths), which ensures data transmission. There is also a time division multiplexing (TDM) technology that can help transmit data by interleaving channels for a certain amount of time.
However, there is another option that could perfectly complement the aforementioned multiplexing technologies. We are talking about spatial distribution multiplexing (SDM), in which the cable can also use several spatial channels (i.e. space can also be used to transmit information). In essence, SDM technology uses the lateral dimension of the fiber to separate the channels.
However, the problem is that today’s cables are approaching the so-called “Shannon limit”, which is the estimated maximum speed at which they can reliably transmit data. Thus, SDM is considered as one of the ways to solve this problem. But so far, it has been difficult to achieve industry consensus on appropriate standards (that is, doing it in a cost-effective way is not easy, since SDM technology, in its most traditional sense, can simply mean increasing the number of fibers in a cable).
It should be recognized that the new ITU Study Group 15 Technical Report is not yet a standard. But this is the first white paper on SDM technology that has been published with the consent of all standards organizations. The paper defines and analyzes the potential properties of both single strand and multi strand SDM optical fibers.