In Part 2 of our series, we will continue to discuss factors essential to fiber optic connectivity. This includes lateral alignment, angular alignment and end separation, as well as what they are and how they affect optical power.
Lateral Alignment
Lateral alignment refers to the degree of being parallel for either the ferrules or the optical fibers. Misalignment occurs when either one of these components is offset from each other rather than lined up. This is different from angular misalignment because it refers to the variation of the components in one direction, while angular misalignment refers to the discrepancy due to rotational error.
A loss in optical power will occur with lateral misalignment. This mismatch prevents some of the light from the transmit optical fiber to enter the cladding of the receive optical fiber. As the lateral misalignment increases, optical power decreases due to the loss in transmission.
Lateral misalignment can occur for two reasons:
- The first reason occurs when the openings of the receive and transmit ferrules are not perfectly matched up. This may be due to poor alignment within the adapter. Adapters are devices used to provide initial alignment of the ferrules and to hold the aligned ferrules in place. This alignment is performed using a sleeve, typically made of a metal alloy (good alignment properties) or ceramic (better alignment properties). Ilsintech recommends the use of high-quality components in your fiber optic system and the phrase “you get what you pay for” is very applicable here.
- The second reason misalignment can occur is from lack of concentricity of the fiber within the ferrule. Sometimes, the ferrule bore is made to be slightly larger than the clad fiber for easy insertion. An epoxy is used to ensure that the clad fiber is permanently bonded in place. However, on rare occasions, the cable will not set exactly in the center of the opening or the core of the ferrule is not placed exactly in the center. Non-concentricity of either the cable or the core can cause a discrepancy in lateral matching. As we’ve discussed before, Ilsintech sets high standards for its ferrules to ensure a quality product that performs well.
Angular Alignment
While lateral alignment refers to the connectivity of the ferrule or the fiber in one direction, angular alignment speaks to the connectivity in any direction. When the optical fibers are connected at an angle (due to angular misalignment) rather than in a perfectly straight line, this results in angular misalignment. This can be slightly more complex than the lateral factor as it considers how offset the coupling faces are in any direction rather than on one parallel plane.
This is one of the more difficult challenges in fiber optic connectivity because it is so common and difficult to avoid without effective and precise equipment. While some cables and connectors are designed to withstand a specific margin of tolerance or degree to which the components are mismatched, it is still critical to be as precise as possible.
When angular misalignment occurs, there is a loss of data transmission. If the faces are not precisely coupled to a minute degree, then light will be lost while traveling from the transmit to the receive cable. The result is not only lost power but higher costs. It is much more cost effective to be as precise as possible with all connectivity components. In the end, less power loss will render a more cost-effective method.
When angular misalignment occurs, there is a loss of data transmission. If the faces are not precisely coupled to a minute dAs we mentioned previously, the first step in good alignment is the use of an excellent adapter with a quality sleeve. Again, the sleeve, typically made of a metal alloy (good alignment properties) or ceramic (better alignment properties) is your first step in transmission.gree, then light will be lost while traveling from the transmit to the receive cable. The result is not only lost power but higher costs. It is much more cost effective to be as precise as possible with all connectivity components. In the end, less power loss will render a more cost-effective method.
The second step in minimizing angular alignment has to do with the installation of the fiber within the ferrule. Cylindricity of the bore opening plus a tight-tolerance fit of the fiber leads to correct placement of the fiber core in order to facilitate a good connection.
End Separation
End separation occurs when the ends of transmit and receive fiber optic cables are not precisely connected to each other. Rather than being completely flush, there will be an air gap between the components.
This is a result of the joining hardware or the ferrules that host the fiber optic cables. If they are not precisely coupled together, then a gap between cable ends could occur. The air gap can be caused by dirt and contamination (debris, moisture, oil, etc.), an improperly polished connector endface (where the connector is not polished to a proper radius), wear and tear (the endface may have a scratch or chip), or improper combination of ferrule types (such as attempting to connect an APC connector to a UPC connector). Many times, though, it is the result of not fully inserting and securing the connector in the mating sleeve of the adapter.
Ilsintech uses a precise polishing procedure to produce the correct endface condition of the ferrules. As part of the acceptance process, each terminated ferrule is subjected to examination using interferometry and microscopes to inspect for the correct shape and contamination. Ilsintech recommends that care be used in the field, and that appropriate cleaning supplies (wipes, swabs, etc.) be used to ensure a quality connector.
While there is a degree of tolerance, the greater the distance between these ends, the greater the power loss. When the components are precisely coupled, light can flow freely from one end to the other. However, if there is a gap, the light will not be transmitted properly and power is significantly reduced.
Ilsintech manufactures ferrules used to make splice-on-connectors and to make connectors for cable assemblies. After creating the ferrules and machining the various features, each ferrule is subjected to multiple measurements to ensure compliance to internal standards (Ilsintech typically uses a higher internal standard than what can be found in general specifications). Each ferrule is graded according to dimensional performance (including bore diameter) and identified for where it will be used, or potentially discarded if it does not meet Ilsintech standards for performance. Ilsintech uses the best of the best to make connectors. Contact America Ilsintech today at 972-556-0916.
