Trends in the Development of Fiber Optic Communication

Nowadays, countless industry digital scenarios such as smart factories, smart logistics, smart cultural tourism, etc. have emerged, accelerating the generation of massive data, which requires more powerful computing and communication ability. This is also the source power of ICT.

We should move the point to 5G when talking about wireless networks, while it should be optical fiber when it comes to wired networks. In this article, we will discuss about optical fiber communication and how it handles IoT and big data.

Currently, the methods for optical communication to expand its transmission capacity are very clear. There are two ways: Firstly, continue to improve the single-wave capacity, which is equivalent to widening the road. Secondly, upgrade all routing switching nodes to achieve point-to-point direct access to expressways and avoid transfers.

There are two main ways to increase the single-wave rate: use a higher-order modulation method and expand the baud rate.

Although high-order modulation can double the speed, it has poor anti-noise ability. That is, just like the wireless air interface, if the external environment deteriorates or the transmission distance is long, high-order modulation cannot be used and only the price can be reduced.

More useful than higher-order modulation at high baud rates. It can increase the speed without affecting the transmission distance. However, high baud rates are very demanding on optoelectronic devices. To put it bluntly, it is a process problem.

In addition to increasing the single-wave capacity, if you want to increase the transmission rate of a single fiber, you can only make this fiber transmit more waves. If you want more waves, you can only further expand the spectral bandwidth of optical communication.

Notes:

single-wave capacity * the number of wave=optical fiber capacity

In fact, optical communication also relies on spectrum resources like wireless communication.

The optic of different frequency bands is transmitted in one optical fiber. Under the premise of considering the guard interval, the larger the available spectrum bandwidth, the more wave numbers of optic that can be transmitted, and the larger the capacity.

In general, the channel uses the C-band and the spectrum resource is 4THz. After expanding to the CE band, the spectrum resources increase by 20% to 4.8THz. If the C++ band is used, it is 6THz. If the C+L band is used, it is 11THz, which is 175% higher than the C band.

If the rate of a single wave is 400G and the C++ band (80 waves), then the backbone transmission capacity can be increased to 400G×80 waves=32Tbps.

In order to further increase the speed, experts have not given up making a fuss about optical fibers. New fiber optic transmission technologies, such as MCF, FMF and PCF, are now becoming a hot spot in the industry.

In addition to increasing the rate and bandwidth, another means is to upgrade and expand the switching node, which is also the essence of the all-optical network 2.0.

The development goal of optical communication is to replace all electrical paths. In other words, all data transmission should be completed by the optical path. Optical fiber should be spread not only to the home, but also to every room, every PC, every TV, and every refrigerator. All fixed network access are replaced with optical.

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