As the demand for faster speeds has grown rapidly over recent decades, new communications networking equipment and systems are constantly being developed to accommodate these requirements. One result of these efforts is a series of established networking protocols and terminology that are used to identify various speed thresholds and the related equipment.

Latency is a term that is used to describe a time delay in a transmission medium such as a vacuum, air, or a fiber optic waveguide.  In free space, light travels at 299,792,458 meters per second.  This equates to 299.792 meters per microsecond (µs) or 3.34µs per kilometer.  In fiber optics, the latency of the fiber is the time it takes for light to travel a specified distance through the glass core of the fiber.  Light moving through the fiber optic core will travel slower than light through a vacuum because of the differences of the refractive index of light in free space and in the glass.

An Optical Time Domain Reflectometer (OTDR) is an optical measurement instrument designed to detect faults, splices and bends in optical fiber cables.  It functions by launching pulses of light into the optical fiber and measuring the back reflections created by the faults, splices, and bends.  It can identify the exact location of the fault by measuring the round trip time from the launch to the detection of the reflected returning pulse.  The time is determined by the speed of light in the glass core of the optical fiber.

Fiber optic splitters enable a signal on an optical fiber to be distributed among two or more fibers.  Since splitters contain no electronics nor require power, they are an integral component and widely used in most fiber optic networks.  As a basic example, the diagram below shows how light in a single input fiber can split between four individual fibers (1x4):

Chromatic dispersion is a phenomenon that is an important factor in fiber optic communications.  It is the result of the different colors, or wavelengths, in a light beam arriving at their destination at slightly different times.  The result is a spreading, or dispersion, of the on-off light pulses that convey digital information.  Special care must be taken to compensate for this dispersion so that the optical fiber delivers its maximum capacity.

The term latency refers to the time delay in a particular system. For communications systems, latency is an important factor, because transmission delays can affect the quality and reliability of the system. In the case of fiber optic networks, latency is the time delay that affects light as it travels through the fiber optic network.

Engineers performing fiber optic network simulation testing with the goal of certifying that their equipment will work as intended once deployed in the field, often require the use of optical fiber spools to complete these procedures.  Since it is crucial these tests produce both correct and reliable results, below are some tips for ensuring the most positive results.

Benchmarking is a term that is used widely to evaluate one's performance against a standard, which is typically based on the best organizations or processes in your industry.  In most cases, the goals of benchmarking are often centered around key factors such as quality, time, and cost.  In the performance of fiber optic communications systems, benchmarking generally applies to the performance quality of the information provided, but on a second level has an extremely significant impact on both time and cost.

The International Telecommunication Union (ITU) is a United Nations agency involved with the development of worldwide standards for communications technology.  With the explosive growth and use of fiber optic technology around the world, a number of single mode optical fibers have been designed over the years for various applications.  Since integration of a variety of optical fibers and systems is required to achieve seamless worldwide communication, ITU developed standards for fibers that help to ensure this can happen.

What exactly is a PON?  What is the difference between EPON and GPON?  With passive networks becoming very prominent across the communications industry, we’ve outlined some of the most commonly used terms along with their definitions, to help readers become more familiar with this particular technology.  (If you would like to suggest additional related PON terms, feel free to comment and we will update the list accordingly)