There have traditionally been two primary camps in the optical fiber industry. These guys do everything with my fiber, more consideration of distance, bandwidth, and future-proofing will allow them to take this charge. Then there is the multi-mode camp, the dabbling of optical fiber. Their philosophy is that short-distance optical fibers are needed in networks, cameras, and special applications.
Multimode fiber enables them to camp longer distances than copper-UTP cables and at a lower cost than single-mode electronics. Obviously, not everyone uses only single-mode or multi-mode fiber, because many end-users and installers use both types of fiber, but in this article, I think that the use of multi-mode fiber is running out.
Multimode fiber-whether to use it or not, it’s a question-thank you, Shakespeare. I have always said in my fiber optic class that, technically speaking, there is only one reason for the existence of multimode fiber. Technology plays no role in this reason. Everything has to do with you getting it, good old money, or the cost of the network. I have always believed that single-mode fiber is always a better choice when considering performance, upgradeability, distance, and bandwidth. The real reason for the existence of multimode fiber is the price of electronic products, more precisely the price of light sources.
For decades, multimode optical fibers have used LED light sources to generate signals. Compared with single-mode fiber lasers, the only real advantage of LEDs is the significant savings in price. Once, I remember, yes, I was measuring the price difference of my multi-mode 100mbps converter, which was 10 times cheaper than a single-mode converter. For this reason, multimode fiber is very suitable for local area networks: in the LAN world, the limited distance provided by LEDs does not limit its use. In fact, multimode fiber can provide a distance of 2 kilometers at a speed of 100 Mbps, which is sufficient for most networks. Multimode optical fiber is booming in the field of networks and cameras. What a great era this is.
A few years ago, with the advent of 1gbps-1000mbps Ethernet, the situation of multimode fiber changed. When this new internet speed hit the market, something happened. First, the traditional LEDs that we like very much have a longer service life than them. The operating threshold of the LED is about 620mbps, which means that the light source cannot provide the needs of 1gig-1000mbps.
The solution to this problem is to replace the traditional LED with a vertical-cavity surface-emitting laser (VCSEL). This new light source is still quite cheap, but it can be handled, and to this day, network speeds are as high as 10 Gbps. So the problem is solved, right? Not so fast… We found that the standard FDDI used for all multimode fibers has never been tested for use with VCSEL light sources. In further testing, we found that the standard cannot reach the speed of 1gig. . Well, technically, the speed is achievable, but only by using expensive patterns to condition the patch line.
Multimode fiber has a design flaw that needs to be resolved, so a new standard for multimode fiber has emerged. This new multimode, LOMMF laser-optimized multimode fiber corrects the problems of the old FDDI standard. LOMMF is currently divided into 5 new standards, OM1-62.5/125, orange coat, OM2-50/125, orange coat, OM3-50/125, Aqua coat, OM4-50/125, North American Aqua coat, European magenta coat, and New OM5-50/125, Lime Green jacket.
When you consider choosing a multimode standard, I think one thing restricts the use of OM1 and OM2, that is, neither of these two types of fibers can support 10gbps Ethernet over 40 meters. When recommending multimode fiber, I strongly recommend using OM3 or higher multimode fiber for 10gbps applications. OM3 is 300 meters and OM4 is 550 meters. Please remember that the price of your network is not the price of the equipment, nor the price of the optical fiber. The labor cost during the installation process increases the budget, so the cost difference between OM1 and OM2 and OM3 or OM4 is compared with the life span of OM3 and OM4. meaningless.
We all know that nothing is stagnant, and network speeds are always improving. time does not wait. With the advent of 40 and 100 Gbps-400 and 800 Gbps Ethernet, multimode fiber needs an answer, and the answer is not always simple. Knowing that the current peak speed of the vessel is 10 Gbps, how do we use multi-mode fiber to achieve the requirements of 40 and 100 Gbps?
This is a double answer. Knowing the 10 Gbps VSCEL limit, the speed of 40 Gbps requires the use of multiple 10 Gbps alleys, meaning to get 40 g requires us to use 4 OM3 or OM4 fibers 4 x 10 g in each direction or 8 = 40 g total fiber “lane” “Bidirectional 40 g transmission, OM3 fiber-8 = 100 meters, OM4-8 fiber = 150 meters, 100gig is the same, except now we need 10 threads or 20 total fibers in each direction OM3-20 fiber = 100 meters, OM4-20 fiber = 150 meters. Remember the OM5 I mentioned? This is where it came from. OM5 is the only multi-mode transmission capable of SWDM (Short Wave Division Multiplexing Transmission), which means that we can use 4 multiplex 10gig vessels on two fibers, one for sending and one for receiving. OM5 multiplexes 850, 880, 910, and 940nm to achieve the required 40 Gig. Is it getting more and more interesting?
So now the real question is, what about single-mode? We know that as a technology, there is nothing better than single-mode fiber. This is known, but what about the huge price difference in equipment costs? As I said before, the difference between multi-mode and single-mode devices is up to 10 times more than single-mode devices, but this is the past. In the past few decades, we have seen a sharp drop in the price of single-mode lasers, and the cost of related equipment has also been drastically reduced.
The price difference between the multimode and single mode 1Gigabit SFP is $2. Remember, multi-mode 1gig SFP can give us a distance of 2 kilometers, the weakest single-mode SFP is 10 kilometers, and the larger distance can reach 80 kilometers. When looking at 40gig SFPs, the price of the single-mode version is an average of $5 higher, but considering that the multi-mode version reduces the distance to 550 meters, the single-mode version keeps a minimum of 10 kilometers.
So should we consider a full single-mode installation? In my opinion, this is not something we should consider, this is something we should encourage. An important fact about fiber prices is that single-mode fiber is always cheaper. Looking at the price of bare fiber, a typical Corning SMF28 Ultra is priced at US$0.08/meter, OM3 is US$0.20/meter, and OM4 is US$0.30/meter. If you calculate the cost separately, it will cost you about US$8.00 per 100 meters of single-mode fiber optic cable, where OM3 is US$20.00 and OM4 is US$30.00 per 100 meters.
This saves at least $12.00-$22.00 per fiber per 100 meters of length. Why today’s single-mode fiber is a more expensive installation? When we consider the difference in equipment SFP price between multi-mode and single-mode, please keep in mind that the difference of $2 for 1 Gig and the difference of $5.00 for 10 Gig, single-mode every time win. When considering 40 and 100gig applications, OM3 and OM4 require 8 and 20 optical fibers for multi-channel transmission. Compared with single mode, the cost savings of optical fibers is amazing.
One of the more important facts I mentioned in this article is the installation cost and the life of future optical fiber proofing. When installing a single-mode fiber optic cable, you can expect that this will be the last fiber you need to use. As mentioned earlier, I have always believed that single-mode fiber is always a better choice when considering performance, upgradeability, distance, and bandwidth.
So to summarize, when you ask, in my application, which fiber is the best? There is actually only one answer-SINGLEMODE-which provides the longest life, longest distance, and highest performance, and now I think I would never say that this is the cheapest option. Long live single mode!
