Fiber optic connector is a device that allows detachable (movable) connections between optical fibers. It precisely connects the two end faces of the optical fibers to maximize the coupling of the optical energy output from the transmitting fiber to the receiving fiber, and minimize the impact on the system caused by its intervention in the optical link. This is the basic requirement of fiber optic connector. To some extent, fiber optic connectors affect the reliability and performance of optical transmission systems. To learn more about fiber optic connectors, you can refer to this article: Complete Guide To Fiber Optic Connector Types.
However, due to the outer diameter of the optical fiber is only 125um, and the light passing part being smaller, single-mode fibers are only about 9um, while multimode fibers are 50um and 62.5um, so the connection between fibers needs to be precisely aligned. When all optical fibers are inserted into the connector, they are not ground. In order to ensure better contact between the end faces of the two fibers, the ferrule end face is usually ground into different structures PC, APC, UPC.
Connector requires the same end face structure to achieve docking. For example, APC and UPC cannot be combined together, otherwise the performance of the connector will be reduced. But the docking of different end faces can be achieved through an adapter.
To understand the differences between the three ferrule end faces, please refer to this article: What are the 3 types of optical fiber ferrule end face?
From above video, we can know that the component that fixes the optical fiber in the connector is the ceramic ferrule, and the thing that fixes the ferrule is the ceramic sleeve. These two components are the most critical factors that affect the quality of the connector.
Core component 1: Ceramic Ferrule
The core component that affects the connector performance is the ferrule. The quality of the ferrule directly affects the precise center connection of two optical fibers. Therefore, you must focus on the ferrule when buying. So what kind of ferrule is good?
Ferrules are made of ceramics, metals or plastics. Ceramic ferrules are widely used. The main material is zirconium dioxide, which has the characteristics of good thermal stability, high hardness, high melting point, wear resistance, and high processing accuracy.
Generally, the most important indicator to measure the quality of ferrules is concentricity, 0.5,1.0, 1.4, etc, the figure is smaller, the performance is better.
Core component 2: Ceramic Sleeve
The sleeve is another important component of the optical fiber connector. Its main function is to align it to facilitate the installation and fixation of the connector ferrule. The inner diameter of the ceramic sleeve is slightly smaller than the outer diameter of the ferrule, and the slotted sleeve tightens the two ferrules to achieve precise alignment.
The ceramic sleeves used in Yingda connectors are designed and produced according to strict standards and are fully automated and strictly classified. All sleeves with the best parameters and the highest precision are used to ensure accurate docking.
How to verify the quality of the connector?
When the connector is ground accurately, the connector loss performance is also different due to the different ferrule end faces. The optical performance of the fiber optic connector is mainly measured by two basic parameters: insertion loss and return loss.
What is insertion loss?
Insertion Loss (often referred to as “IL”) is the optical power loss caused by connections. Insertion loss is mainly used to measure the optical loss between two fixed points in the optical fiber. It is usually caused by the lateral deviation between the two optical fibers, the longitudinal gap in the optical fiber connector, the end face quality, etc. The unit is expressed in decibels (dB). The smaller the value, the better. The general requirement should not be greater than 0.5 dB.
What is return loss?
Return Loss (usually abbreviated as “RL”) refers to the parameter of signal reflection performance. It describes the power loss of optical signal return/reflection. Generally, the bigger the better, and the value is usually expressed in decibels (dB). Generally, the typical RL value of APC connector is about -60dB, and the typical RL value of PC connector is about -30dB.
In addition to the two optical performance parameters of insertion loss and return loss, the performance of optical fiber connectors should also pay attention to the interchangeability, repeatability, tensile strength, operating temperature, number of insertions and removals, etc. of the optical fiber connector when selecting a good optical fiber connector. Yingda disclose the technical data of fiber patch cord connectors in this article: Fiber Patch Cord Production Line Test Standard -Yingda
