Can fiber be bent? How much can it bend at the bottom? While understanding this problem, we need to first understand the principle of optical fiber transmission.
Have you ever experienced a sudden disconnection of WIFI, have you experienced repeated restarts, and still feel that the network speed is slow? In addition to the router itself, the cause of these problems may also be a problem with the fiber optic cable in your home.
The propagation of light in an optical fiber is mainly based on the principle of total reflection. When the light is perpendicular to the end face of the light and coincides with the axis of the optical fiber, the light propagates forward along the axis. If you bend too much, it will cause part of the light to fail to pass normally, which will also cause the optical power to drop, resulting in poor quality received. The speed is slow.
A certain degree of large-angle bending leads to an increase in the loss of the optical fiber, which reduces the signal-to-noise ratio. If the signal-to-noise ratio is small, the bandwidth may be small (actually, the number of damaged packets increases and the number of retransmissions increases).
Under normal circumstances, when the optical fiber is long, it can be coiled into a ring and then bundled together, but it should be noted that the diameter of the circle should not be too small, so as to avoid excessive curvature and the optical signal cannot be refracted and transmitted to the opposite end. Generally, the diameter should not be smaller than 10 cm (that is, the radius is 5 cm) is appropriate, remember not to fold in half.
Fiber Bend
Radiation loss from fiber bending
Optical fibers are flexible and can be bent, but after bending to a certain extent, although optical fibers can guide light, the transmission path of light will change. The transmission mode is converted into a radiation mode, so that a part of the light energy penetrates into the cladding or passes through the cladding as a radiation mode that leaks out and is lost, resulting in loss. When the bending radius is greater than 5-10cm, the loss caused by bending can be ignored.
Usually, what we see are fiber optic cables with white outer skins. After the fiber optic cables are used in the home, the technician will roll up these white fiber optic cables and tell you that they are fiber optic cables that cannot be folded. Don't touch it. Although, you generally don't listen carefully, this is by no means alarmist. If you accidentally touch the optical fiber when you move something near it, it will cause the optical fiber to be damaged and affect the network speed.
So, once the fiber is damaged, what should we do?
Once the pipeline is broken, we need the help of the fiber fusion splicer. Generally speaking, if something is broken, it needs to be repaired. And the loss of the optical fiber is not called repairing the optical fiber, but the optical fiber needs to be spliced.
In fact, the sluggishness of our home network caused by fiber damage is still a small problem. In the past two years, it is not uncommon for some enterprises to go offline due to fiber damage. Last year, Alipay had its optical fiber cut, causing the Alipay server to go down and the business to go offline. We can find that once the optical fiber of the enterprise is damaged, it will affect the data loss of the entire enterprise, the service will be limited, and the reputation of users will be affected. So what kind of light can meet the needs of the enterprise?
Home, business fiber is very different
It can be said that enterprise optical fiber is superior to household optical fiber in terms of transmission speed and anti-breakage ability. When you walk into a data center, you will find that there are not only optical fibers, but also optical cables that are more "conspicuous". Optical cable is also a kind of optical fiber, and the inside of optical cable is also composed of multi-core optical fibers, so it is thicker and has stronger transmission capacity.
If we want to differentiate enterprise fiber, we need to understand the concept of singlemode and multimode. The distinction between single-mode and multi-mode is the difference in the transmission mode of the signal in the fiber. The core size of the single-mode is generally 8--10um. In the single-mode, the signal propagates along a straight line, that is, a mode of propagation.
The multi-mode fiber core is relatively large, 50um or 62.5um, and can transmit multiple modes at the same time.
When enterprises choose optical fibers, they should consider their own transmission distance and transmission bandwidth. Generally, single-mode is used in the long-distance (more than 5 miles) transmission process, and we use single-mode fiber for fiber-to-the-home. While multi-mode is concentrated in short-distance complex signal transmission, it can be used for vertical hedging and short-distance building group wiring within 550 meters of Ethernet. That is to say, although single-mode fiber has a low signal attenuation rate and high transmission speed, multi-mode fiber is the most widely used mode in enterprise applications.
