Buying Optical Fiber for Network Testing and Latency Applications

When the time comes to buy spools of optical fiber for testing and demonstrating communications systems, there are a few items to consider that will help ensure you end up with an ideal setup.  Since it has been proven that following a few best practices will help you get the most out of your fiber, thinking about these four important items in advance will allow you to further qualify your needs as well as speed up the purchasing process.
1.  Fiber Types & Manufacturers
There are many different optical fibers used in communications networks, so determining the specific type is very important.  Do you need single mode or multimode fiber?  Are you seeking to simulate a field network that requires an exact fiber match, or will an industry-standard equivalent suffice?  Also, keep in mind that both pricing and availability of fiber does vary by type and manufacturer, so you will need to consider this as well during the project planning phase.
2.  Fiber Lengths and Configurations
Once you have selected the appropriate type(s) of fiber, the next step is to determine the lengths needed for your test setup.  Depending upon your solution partner, which we will cover later in this article, there are potentially a number of configuration options available to you.
Will your setup include more “standard” lengths that will apply to many different tests, or will it require very specific lengths like in the case of a fiber latency / optical time delay application?  Is it preferable to use longer continuous lengths, or is having several shorter lengths for distance flexibility more ideal?  Lastly, do you plan to use this fiber for a single set of tests in the short-term, or might it be used for a variety of different tests over the long-term?  (If the latter, it may be beneficial to think about lengths with the bigger picture in mind from a planning perspective)
3.  Enclosure Type
In terms of enclosures for your fiber spools, there is no question that you should always utilize them, since there are too many risks related to using unsecured and unprotected spools.  From the cost of replacing broken fibers and the potential for unreliable test results, to your setup looking sub-standard versus a competitor who did follow this best practice, this is an absolute must and a solid investment.
At a high level there are two primary categories, portable and rack-mount, which than have many variations.  This is fairly straightforward as each has its respective advantages, so your decision is based solely upon the preferred setup for the application/environment.
Depending upon the solution vendor you decide to partner with, there may be more or less enclosure options available to you.  In many cases, the length configurations you have determined will help to narrow down the types of enclosures that a given vendor can provide from their portfolio to meet your needs.
4.  Solution Partner / Vendor Selection
Since the leading fiber manufacturers focus on mass production of standard lengths and do not provide enclosures, selecting a proven solution partner that specializes in selling fiber as part of a quality testing platform is important.  While it may seem like installing a spool of fiber in an enclosure is simple, working with bare fiber is not easy.  It requires well-designed hardware, skilled professionals, specialized equipment, and very hands-on processes to ensure a great finished product.
Important Note:  It takes time for even the most qualified vendors to build and deliver these types of quality platforms, from fiber availability through time/labor for careful spooling, assembly, and testing procedures.  Therefore, it is always recommended to plan in advance and not wait until last-minute when seeking to acquire fiber.
It can be very detrimental and costly if this aspect is overlooked and/or if cost is the only driving factor when choosing a vendor.  Experience, capabilities, available options, and services are all key factors to inquire about and review during the selection process.
In conclusion, by taking all of these considerations into account prior to making a fiber purchase, it will go a long way to ensuring your setup will provid maximum value to your organization, while making the entire process easier.

Optical fiber beyond telecommunication

Optical fiber is great for carrying huge amounts of data over long distances at unimagined speeds and providing us with high-speed Internet connections that nowadays are more a necessity than a luxury, but they also have an excellent throughput in other fields beside telecommunications, since they are used from non-invasive surgeries to pool illumination.
Optical fiber made it possible for surgeries to be minimally invasive and to have advanced diagnostic technologies due to implements like optical fiber cameras. Medical optical fiber applications also include X-ray imaging, ophthalmic lasers, light therapy, dental head pieces, surgical microscopy and endoscopy. The study “Global Market Study on Medical Fiber Optics: Asia to Witness Highest Growth by 2019” says that medical fiber global market will reach a value of USD 1,336.1 million by 2019.
Optical fiber is used in the decoration field because it provides an attractive and economical way of illumination. It is used at museums exhibitions due to their heat-free attribute and in underwater lighting because they don’t conduct electricity.
Optical fibers also provide extremely focused light, they are long-lasting, look like neon, colors can change according to the applied filter and their installment and maintenance is easy. Also they look really cute, don’t they?
Lighting applications with optical fiber are being used in the automotive industry too because they it can be installed in reduced spaces and it transmits cold light. Companies like Volvo, Audi, BMW, Jaguar and Saab use fiber to build the communication system that connects sensors with airbags and traction control devices in order to increase passenger’s safety.
Roll Royce’s trademark “Starlight headliner” is built with over 1300 optical fibers which make Phantom’s ceiling look like a starlight night.
Optical fiber sensors measure, pressure and strain. But they are also used to look for displacements, vibrations and rotations in civil structures such as highways, buildings and bridges or smart structures like airplanes wings and sport equipment. They are also very helpful for monitoring oil, power cables and pipelines in places that are really hard to reach.
Sensors work with a detector arrangement that measures the subtle changes that happen in the light as it travels through an optical fiber.  They offer a lot of advantages because they don’t require electrical cables, therefore can be safely used in high-voltage and electrical environments.

What Types of Optical Fiber Should I Choose and How Many Fibers?


It may be familiar for you that optical fibers are divided into two different mode which is multimode and single mode.
Single mode fiber has a core that is 8.3 microns in diameter. Single-mode fiber requires laser technology for sending and receiving data. With a laser used, light in a single mode fiber also refracts off the fiber cladding. Single-mode has the ability to carry a signal for mile, making it ideal for telephone and cable television on providers.
Multimode fiber, as the name suggests, permits the signals to travel in multiple modes, or pathways, along the insides of the glass strand or core. It is available with fiber core diameters of 62.5 and a slightly smaller 50 micron. 62.5 micron multimode is referred to as OM1. 50-micron fiber is referred to as OM2, OM3, and the recently added OM4. OM4 has greater bandwidth than OM3 and OM3 has greater bandwidth than OM2.
While single mode fiber has a core that is 8.3 microns in diameter. Single-mode fiber requires laser technology for sending and receiving data. With a laser used, light in a single-mode fiber also refracts off the fiber cladding. Single-mode has the ability to carry a signal for mile, making it ideal for telephone and cable television on providers. 50-micron OM3 fiber is designed to accommodate 10 Gigabit Ethernet up to 300 meters, and OM4 can accommodate it up to 550 meters. Therefore, OM3 and OM4 fiber are always chosen over the other glass types. In fact, nearly 80% of 50-micro fiber sold is OM3 or OM4
Except for the fiber mode, the number of fibers is necessary to know. Usually, unless you are making patch cords or hooking up a simple link with two fiber, it is highly recommended that you include a number of spare fibers. Corporate network backbones are often 48 fibers or more. Most backbone cables are hybrids – a mix of 62.5/125 multimode fiber for today’s networks and single-mode fiber for future networks. If the slowest network planned today is as gigabit speeds, it might even be better to use the new 50/125 multimode fiber optimized for the laser sources used in gigabit networks.

Learn to choose the right fiber in minutes


How to select a right optical fiber?
  The basic requirement when selecting the optical fiber is that the optical power coupled into the optical fiber from the emitting light source should be large enough, and the distortion generated after the optical signal is transmitted through the optical fiber is minimal.
Low transmission attenuation
  In a particular wavelength range, the attenuation must be small enough to allow the relay distance to be as long as possible while meeting the optical power required by the receiver. When designing the system, consider the insertion loss of connectors, connectors, and couplers, and the amount of headroom required for system operation. For this reason, the correct choice of operating wavelength and fiber type.
Low coupling loss
  Coupling losses include light source coupling loss and detector coupling loss. When the core size and numerical aperture are large, the coupling loss of the light source can be reduced, but the detector coupling loss increases. In order to reduce the coupling loss with the detector, it is required that the core size and the numerical aperture be sufficiently small so that the outgoing light of the optical fiber completely falls on the receiving surface of the detector. In order to improve the response speed of the receiver and reduce the noise, the area of ​​the detector is required to be small, so the method of increasing the photo-sensitive surface of the detector cannot be used to reduce the coupling loss. Fibers with a large core size and numerical aperture have a small transmission bandwidth and are suitable for systems using LEDs.
Low connection loss
  Connection losses include loss of connectors and connectors. The core diameter tolerance, out-of-roundness, and core and cladding concentricity errors are as small as possible to obtain the minimum connection loss. To increase the geometrical accuracy of the optical fiber, it is necessary to increase the manufacturing cost. Increasing the size of the core and the numerical aperture can reduce the adverse effect of the geometrical tolerance on the connection loss, but it is inconsistent with the increase of the bandwidth and a comprehensive consideration must be taken for the compromise.
Dispersion and bandwidth
  In order for the modulated optical signal to pass through the full length of the optical fiber with minimal distortion, the dispersion of the optical fiber is required to be sufficiently small. In order to reduce fiber dispersion, the refractive index distribution index and the zero dispersion wavelength must be strictly controlled. For a specific system, the fiber type and working wavelength should be selected correctly. For example, a long-distance, high-rate submarine cable system should use a G.654 fiber with a zero-pigment shift of 1.55 μm. The wavelength-division multiplexing system should choose a small dispersion system. However, the non-zero but G.655 fiber reduces the four-wave mixing but has an adverse effect. The DWDM system used in the metropolitan area network must be a full-wave fiber with an extremely wide wavelength range and a wide range of available wavelengths. Systems using LEDs must fully consider the effects of material dispersion and other factors. The table above shows the typical parameters of a zero-cable single-mode fiber for reference when selecting the fiber.

The Positive Impact of Using Optical Fibers on Cell Towers


While fiber optic technology has been utilized for many years in the communications industry, consumers generally identify with the role that it plays in wired communications such as Cable TV, Fiber-To-The-Home, and the related networking equipment.  However, what most overlook or do not realize is the significant impact that deploying optical fibers has also had on something consumers use every day – mobile devices.  In order to achieve the high speed data levels that we have become accustomed to when using mobile devices, cell towers and their supporting networks had to be retrofitted with optical fiber cables.

The transition from copper to fiber first started when 3G mobile technology was first introduced, but when 4G LTE technology was deployed, the service providers’ equipment in almost every cell tower had to be upgraded.  The primary reason for this was to support the need for the higher frequencies and faster speeds that the existing 1 5/8 ” coax cables on most cell towers could not handle. Since the primary feed line to most cell towers had been upgraded already, connecting the cell systems in the towers with fiber was the next step.
So what positive changes occurred when transitioning to optical fiber in the cell tower?
First, engineers could now design systems with fiber that run solely off of DC power.  The result was that a very small (less than a ½” in diameter) 16-pair optical fiber cable and two small multi-strand DC cables could replace as many as 12 to 18, 1 5/8” coax cables which are sometimes called “hard lines”.  As you can see, this is a significant improvement.
Secondly, after the hard lines are taken off and replaced with optical fiber cables, both the weight and wind drag are drastically reduced on the cell tower.  The amount of weight and wind drag that is reduced when swapping coax for a fiber-based system is almost unbelievable.  Thousands of pounds of materials are removed and space on the tower is dramatically increased.  In addition to amount of material, a lot of time is saved in comparison to having to add 12 to 18 more hard lines to each system.
By upgrading to incorporate optical fiber cables into the infrastructure, today’s cell towers have realized significant improvements not only in mobile network performance, but also from an architectural standpoint.
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