Optical Fiber
Optical fiber is growing in both telecommunications and data communication due to its unparalleled advantages: the faster speed with less attenuation, less impervious to electromagnetic interference (EMI), smaller size, and greater information-carrying capacity. Relentless bandwidth needs, on the other hand, are also driving significant growth in the demand for fiber optics. Let's review the common types of fiber optic cables, explore the pros and cons of fiber optics, and learn tips on selecting fiber optic cables.
What is fiber optic?
Fiber optics use light pulses instead of electrical pulses
to transmit information, providing hundreds of times the bandwidth of
traditional electrical systems. Fiber optic cable can be protected by sheath
and armor to make it resistant to harsh environmental conditions. Therefore, it
is widely adopted in commercial enterprises, governments, the military, and
many other industries for voice, video, and data transmission.
Common fiber optic cable types
Generally, there are three types of fiber optic cables: both
glass fiber optics - Single mode fiber optic cables, and multimode fiber optic
cables, as well as plastic optical fibers (POF).
Multimode fiber optic cable
Multimode fiber optic has a larger core diameter than single-mode fiber optic cable, allowing multiple paths and multiple wavelengths of light to be transmitted. A 50-micron and a 62.5-micron multimode optical fiber are available. It is commonly used for short distances including patch cable applications such as fiber to the office or patch panel to equipment, data, and audio/video applications in local area networks. According to the refractive index distribution of fiber, multi-mode fiber can be divided into two types: step-index multimode fiber vs. stepped-index multimode fiber.
Single Mode Fiber Optic Cable
The "mode" in fiber optic cable refers to the path the light travels. Single-mode fiber has a smaller core diameter of 9 microns (8.3 microns to be exact) and allows only one wavelength and one path of light to travel, which greatly decreases light reflections and reduces attenuation. It is often used in network connections over long distances even though it is slightly more expensive than its multimode counterparts.
The plastic optical fiber (POF)
POF is a wide-core step-index optical fiber with a typical
diameter of 1mm. The large size allows it to easily couple a lot of light from
sources and connectors that don't need to be high precision. Thus, typical
connector costs are 10-20% higher than fiberglass, and termination is simple.
With minimal tools and training, it is easy to install and more durable as it
is plastic. For applications that don't require high bandwidth over long
distances, POF is more competitive, making it a viable option for office LAN
connections and short, low-speed links.
Benefits and Drawbacks of fiber optics
Although optical fiber has advantages in speed and bandwidth
over copper cable, it also has some disadvantages. Here are the pros and cons
of fiber optic cable.
Benefits of fiber optics
Greater Bandwidth and Faster Speed - Fiber optic cable
supports extremely high bandwidth and speed. A large amount of information that
can be transmitted per fiber optic cable unit is its most significant
advantage.
Inexpensive - Long continuous miles of fiber optic cable can
be made cheaper than equivalent lengths of copper wire. With many vendors
swarming to capture the market share, the price of optical cables would drop
for sure.
Thinner and Lighter: Optical fiber is thinner and can be
stretched to smaller diameters than copper wire. They are smaller in size and
lighter than comparable copper wire cables, providing a better fit for places
where space is an issue.
Higher carrying capacity - since optical fibers are much
thinner than copper wires, more fibers can be packed into a given diameter
cable. This allows more phone lines to pass through the same cable or more
channels to pass through the cable into your cable TV box.
Less Signal Degradation - Signal loss in optical fiber is
less than in copper wire.
Light Signals - Unlike electrical signals transmitted in
copper wires, light signals from one fiber do not interfere with those from
other fibers in the same fiber cable. Having clearer conversations on the phone
or receiving TV signals is a result of this.
Long Lifespan - Fiber optics typically have a longer life
cycle of over 100 years.
Drawbacks of fiber optics
Low Power - A low-power light source is the only option.
Although high-power transmitters are available to upgrade the power supply,
this would incur additional costs.
Brittleness - Optical fiber is rather fragile and more
vulnerable to damage than copper wires. It is better not to twist or bend the
fiber optic cables too much.
Distance - the distance between transmitter and receiver
should be kept short or repeaters are needed to amplify the signal.
How to select the right fiber optic cable?
Fiber optic cable has gained a lot of momentum in
communications networks, and there is emerging a dazzling array of vendors
competing to manufacture and supply fiber optic cables. When selecting optical
fiber, you'd better start with a reliable supplier and then consider the
selection criteria. Here is a guide to clear up some of the confusion about
choosing fiber optic cable.
Check manufacturer qualification
Major optical cable manufacturers must obtain ISO9001
quality system certification, ISO4001 international environmental system
certification, ROHS, relevant national and international institution
certification such as Ministry of Information Industry, Certification UL, etc
Fiber mode: Singlemode or Multimode
As shown above, single-mode fiber is often used for long
distances while multimode optical fiber is commonly used for short spans. In
addition, system cost and installation cost change with different fiber modes.
You can refer to Singlemode vs. Multimode Fiber: What's the Difference? then
decide which fiber mode you need.
Optical cable jackets: OFNR, OFNP or LSZH
The standard sheath type of optical cable is OFNR, which
stands for “Optical Fiber Non-conductive Riser”. Additionally, fiber optics are
also available with OFNP, or plenum ducts, which are suitable for use in plenum
environments such as drop ceilings or raised floors. Another jacket option is
LSZH. Short for "Low Smoke Zero Halogen", it is made from special
compounds that give off very little smoke and are non-toxic when ignited.
Therefore, always consult the local fire code authority to clarify installation
requirements before choosing the type of jacket.
Fiber optic internal construction: tight bundle or break or assembly or loose tube
Tight-wrapped cables are also known as distribution-style
cables, which feature all fibers buffered under a single sheath with strength
members for box-to-box and below-level conduit installations. Fiber optic cable
or ventilation cable is applicable for device-to-device applications with
robust and durable advantages. Zip cord assembly or construction is often used
to make optical patch cables and short drop runs. In the telecommunications
industry, loose tube construction is the standard.
Indoor vs Outdoor
The choice greatly depends on your application. The main
difference between indoor and outdoor fiber optic cables is the water-blocking
feature. Outdoor cables are designed to protect the fibers against years of
exposure to moisture. However, nowadays there are cables with both dry
water-blocked exterior features and interior designs. For example, in a campus
environment, you can get cables with two jackets: an outer PE jacket that is
moisture-resistant and an inner PVC jacket that is UL listed for flame
retardance.
Number of fibers
Indoor and outdoor fiber optic cables have a wide fiber
count option ranging from 4 to 144 fibers. If your fiber demand exceeds this
range, you can customize the fiber count for indoor or outdoor optical cables.
Unless you are making fiber patch cords or connecting a single link with two
fibers, it is strongly recommended that you get spare fibers.
Conclusion
Fiber optics provides a fast, constant and stable Internet
connection that can transmit a lot of data over incredible distances. As data
demands become huge, fiber optic cabling is the sure solution for network
flexibility and stability.
0 Comments