Advantages Optical fiber

Introduction to Single Mode Fiber

SPEED: Fiber optic networks operate at high speeds - up into the gigabits

BANDWIDTH: large carrying capacity
DISTANCE: Signals can be transmitted further without needing to be "refreshed" or strengthened.
RESISTANCE: Greater resistance to electromagnetic noise such as radios, motors or other nearby cables.
MAINTENANCE: Fiber optic cables costs much less to maintain.

In recent years it has become apparent that fiber-optics are steadily replacing copper wire as an appropriate means of communication signal transmission. They span the long distances between local phone systems as well as providing the backbone for many network systems. Other system users include cable television services, university campuses, office buildings, industrial plants, and electric utility companies.

A fiber-optic system is similar to the copper wire system that fiber-optics is replacing. The difference is that fiber-optics use light pulses to transmit information down fiber lines instead of using electronic pulses to transmit information down copper lines. Looking at the components in a fiber-optic chain will give a better understanding of how the system works in conjunction with wire based systems.

At one end of the system is a transmitter. This is the place of origin for information coming on to fiber-optic lines. The transmitter accepts coded electronic pulse information coming from copper wire. It then processes and translates that information into equivalently coded light pulses. A light-emitting diode (LED) or an injection-laser diode (ILD) can be used for generating the light pulses. Using a lens, the light pulses are funneled into the fiber-optic medium where they travel down the cable. The light (near infrared) is most often 850nm for shorter distances and 1,300nm for longer distances on Multi-mode fiber and 1300nm for single-mode fiber and 1,500nm is used for for longer distances.

Think of a fiber cable in terms of very long cardboard roll (from the inside roll of paper towel) that is coated with a mirror on the inside.
If you shine a flashlight in one end you can see light come out at the far end - even if it's been bent around a corner.

Light pulses move easily down the fiber-optic line because of a principle known as total internal reflection. "This principle of total internal reflection states that when the angle of incidence exceeds a critical value, light cannot get out of the glass; instead, the light bounces back in. When this principle is applied to the construction of the fiber-optic strand, it is possible to transmit information down fiber lines in the form of light pulses. The core must a very clear and pure material for the light or in most cases near infrared light (850nm, 1300nm and 1500nm). The core can be Plastic (used for very short distances) but most are made from glass. Glass optical fibers are almost always made from pure silica, but some other materials, such as fluorozirconate, fluoroaluminate, and chalcogenide glasses, are used for longer-wavelength infrared applications. 

There are three types of fiber optic cable commonly used: single mode, multimode and plastic optical fiber (POF).

Transparent glass or plastic fibers which allow light to be guided from one end to the other with minimal loss.

Fiber optic cable functions as a "light guide," guiding the light introduced at one end of the cable through to the other end. The light source can either be a light-emitting diode (LED)) or a laser.

The light source is pulsed on and off, and a light-sensitive receiver on the other end of the cable converts the pulses back into the digital ones and zeros of the original signal.

Even laser light shining through a fiber optic cable is subject to loss of strength, primarily through dispersion and scattering of the light, within the cable itself. The faster the laser fluctuates, the greater the risk of dispersion. Light strengtheners, called repeaters, may be necessary to refresh the signal in certain applications.

While fiber optic cable itself has become cheaper over time - a equivalent length of copper cable cost less per foot but not in capacity. Fiber optic cable connectors and the equipment needed to install them are still more expensive than their copper counterparts.

Single Mode cable is a single stand (most applications use 2 fibers) of glass fiber with a diameter of 8.3 to 10 microns that has one mode of transmission. Single Mode Fiber with a relatively narrow diameter, through which only one mode will propagate typically 1310 or 1550nm. Carries higher bandwidth than multimode fiber, but requires a light source with a narrow spectral width. Synonyms mono-mode optical fiber, single-mode fiber, single-mode optical waveguide, uni-mode fiber.

Single Modem fiber is used in many applications where data is sent at multi-frequency (WDM Wave-Division-Multiplexing) so only one cable is needed - (single-mode on one single fiber)

Single-mode fiber gives you a higher transmission rate and up to 50 times more distance than multimode, but it also costs more. Single-mode fiber has a much smaller core than multimode. The small core and single light-wave virtually eliminate any distortion that could result from overlapping light pulses, providing the least signal attenuation and the highest transmission speeds of any fiber cable type. 

Single-mode optical fiber is an optical fiber in which only the lowest order bound mode can propagate at the wavelength of interest typically 1300 to 1320nm. 

Traditional copper wires use electrical pulses to transmit data from point to point. Fiber optic cables have become a strong alternative to copper wiring because they are more efficient and provide better quality of transmission. Fiber optic wires contain a glass filament and require light pulses to send information.


One of the largest benefits of fiber optic cable over copper wiring is the high resistance to external forces. Fiber optic cable is essentially immune to electromagnetic interference from strong magnetic forces, and is non-conductive and will not hold an electrical charge. The natural electrical insulation of glass makes fiber optic cable essential for environments where an electrical current could be dangerous.

Cheaper Over Time

Although copper wiring costs less per measured distance than fiber optic cable, it requires a lot of additional maintenance and replacement over time. Fiber optic cable lasts longer and provides a better data output for the cost.

Stronger Signal

Using light pulses allows fiber optic cables to transmit data at much faster rates than copper wiring. Because light is prone to less degradation over distance, fiber optic cables can be stretched over longer distances before requiring a component to refresh signal strength.

Benefits vs. Multi-Mode

Single-mode fiber optic cable allows only one stream of light per cable. Multi-mode is able to handle several light streams per cable. Single-mode cable, because it only processes one stream of light, can stretch over much larger distances than multi-mode. It does not experience the signal degradation stemming from multiple light streams converging as in multi-mode cables. The glass core of single-mode fiber optic cable is much smaller than multi-mode cables and enables data to travel faster.

Computer Cabling

CAT3 Wire


Traditional voice grade cable. Supports Ethernet 10Base-T data.

CAT5 Wire


Traditional data grade cable that is rated to 100Mhz for supporting 100 Base-T cable needs.

CAT5 Wire


Enhanced CAT5 cable. CAT5e has been ratified as a cabling standard with stricter specifications than those for CAT5, CAT5e is rated at 100Mhz at a minimum. CAT5e is the cable needed for 10-Base-T, 100 Base-T and Gigabit Ethernet needs.

CAT6 Wire


With ratings up to 250Mhz, this computer cabling standard brings increased performance over and above CAT-5e.

Fiber-optic cable to desktop

Fiber to Desktop

Use of fiber optics in communications is growing. Fiber-optic communications systems have key advantages over older types of communication. They offer vastly increased bandwidths, allowing tremendous amounts of information to carried quickly from place to place.

Copper of Fiber Backbone

Copper or Fiber Backbone

Copper cable is standard for extending any type of communication application over a short lenght: telephone lines, voice connections, or data transmission.

Fiber optic cable allows signals to travel for long distances without the use of repeaters, which are needed to compensate for reductions in signal strength.

Single or Multimode Fiber

Single-mode Fiber is an optical fiber in which only the lowest order bound mode can propagate at the wavelength of interest. Single mode fiber is normally used for long distance, high-bandwidth applications.

Multi-mode fiber is an optical fiber that supports the propagation of more than one bound mode. Multi mode fiber is used for shorter distance transmissions, such as local area networks.

Single mode fiber doesn’t have modal dispersion, modal noise, and other effects that come with multimode transmission; single mode fiber can carry signals at much higher speeds than multimode fibers. They are standard choice for high data rates or long distance span (longer than a couple of kilometers) telecommunications which use laser diode based fiber optic transmission equipment.