Fiber Optic Ferrules

our ceramic machining technologies produce high-precision connector components for fiber optic communications systems, available both with custom and standard designs.

Single-mode optical fibers require precise bore diameter tolerances; any mismatch will lead to reduced light transmission, creating a strong market for ceramic ferrules.

Due to lockdowns, travel restrictions and company closures caused by COVID-19 pandemic, technology events, supply chains and markets across the world have been affected negatively by it.

End-Fitting

Ferrules, commonly referred to as zirconia ferrules, are an integral component of fiber connectors that house and protect fibers while aligning them precisely for optimal transmission of optical signals. Ceramic ferrules offer superior durability and performance over other ferrule materials while offering improved end-face geometry and polishing for low insertion loss and minimal back reflection.

Ceramic ferrules must have extremely accurate bore diameters to allow fibers to line up correctly and transmit data without losing power or experiencing poor connectivity. Any deviation will lead to power loss or poor connectivity which in turn results in power losses and connectivity issues.

Precision in ferrule manufacturing and machining can only be attained through both processes, namely the blank manufacturing and machining processes. Utilizing yttrium-stabilized nano-zirconia powder as the blank material, molds are created using molding tools that mold them to form desired ferrule shapes before being subject to an exhaustive grinding process which achieves submicron level processing accuracy for high quality ceramic ferrules.

Polishing

Zirconia ceramic ferrules are essential in maintaining the performance and reliability of fiber optic connections. Any gap between a ferrule and mating connector sleeve creates an air cavity which creates loss-generating air currents which interfere with optical transmissions causing reduced data transmission rates.

This gap may be caused by dirt on the sleeve abrasively cutting into fiber or ferrule material and leaving behind nicks and scratches that reflect light back to its source. Other possible culprits could include improper endface radius polishing (whether too large or small), mismatched ferrule types (for instance connecting an APC with UPCs), improperly polished endface radiuses or incorrect polishing methods used.

Aluminum oxide polishes provide the optimal final polish because it doesn’t damage ceramic ferrules or glass fibers, and should be used in circular “figure 8” motions until no film scratching can be seen on the endface. Furthermore, regularly cleaning your polishing pad helps ensure peak performance from its polishing material.

Alignment Sleeves

Fiber optic cables must align perfectly with each end to be effective data transmitters, which requires great attention to detail and exact tolerances. Any deviation could result in loss of transmission.

Ceramic ferrule tolerances are tightly managed to ensure high-performance connectivity. Singlemode connectors’ smaller core sizes necessitate more stringent control on bore diameter tolerance, with any slight variations leading to mismatch and decreased performance of their connectors.

UCL Swift is proud of their successful creation of an alignment sleeve capable of compensating for bore-diameter variations, featuring beveled surfaces 56 for both larger and smaller ferrule apertures 18 & 20, along with stop surfaces 60 that align precisely the end face 72 of 2.5mm or 1.25mm ferrules received into each aperture in a mating relationship within the sleeve.

Testing

Ceramic ferrules with the appropriate cylindricity are critical to ensure optimal optical connections. Cylindricity refers to three-dimensional circularity; its dimension must fall on one of the axes of the ferrule for proper fitting between two ferrules.

Polishing the ceramic ferrule to ensure quality end-face is also critical in producing an end-face of high quality. Overpolishing may lead to pitted and scratched surfaces that increase power loss; to prevent this from happening Ilsintech employs an exact polishing procedure which guarantees fiber end-face meets requirements of high-grade connectors.

Verifying that epoxy has been distributed sufficiently into a ferrule bore is easy, since an epoxy bead will appear on its surface. But ascertaining there is enough epoxy within requires special tools and testing swabs; otherwise too little epoxy could prevent the clad fibers from setting properly within their head portions of ceramic ferrules, which in turn decreases optical power transmission and cause misalignments of optical power transmission lines.