It gives transmission distance. Types fiberoptic

• Single mode (single mode): Only one mode light propagates. Allow distances up to 400 km and very high speeds. The usual size of 9/125 microns fiber is.
• Multimode (multi mode): The light is spread by more than one way. . Used for transmission at close range, no more than 2 Km Typical multimode fibers are according to ISO: OM1 (62., Data transmission is changing direction. In a duplex system, each of the fibers is used for transmission in one direction. Therefore, the duplex installations are faster and more efficient.

As network cables, fiber optic cables have their international standards. In this instance they are divided into OM1, OM2, OM3 and OM4. The difference between them is based on differences in bandwidth, speed, inside diameter as seen in the table below. To help clarify some concepts, would 9/125 (inside diameter/outside diameter). In the bandwidth can be 850nm, 1350nm or one550nm (nanometers). In the case of application we have put a guidance to help understand the concept, but actually it can be used in many areas.

The case MMF multimode fibers is when the core optical fiber is larger than the coating and it happens that a ray of light propagates through the fiber as multiple beams or modes. So the input and output have differences, this is also because many of the rays lose energy becoming heat. In multimode fibers the time dispersion and attenuation is greater than on other dand fiber. We show you a table for variations in multimode fiber.

It is very important to know the type of polishing used in a facility, as it will help us to reduce light losses in the different links.
There are currently 4 types of polishing, although the most used are PC polishing (flat polishing) and APC polishing (polishing with an angle).

• FLAT or plane: It is used in multimode installations and its cut is flat. The return loss oscillates in <-30db.
• PC or Phisical contact: It was usedin single-mode and multi-mode installations. It is the most common polishing in fiber facilities.
  Its polishing is convex and it has the best properties of loss of return, between <-35db.
  Its connector is blue.
• UPC or Ultra Phisical Contact: Used for single-mode fiber installations. It is equal to the polished PC, but it does not reflect as much light as the polished PC.
  Your return loss is around <-55db. It is a polish usedin digital systems and telephony installations.
  Its connector is Blue.
• APC or Angled Physical Contact: This is an 8 degree angular polish. With a loss return of <-65db.
  Its connector is green.