Ceramic Ferrules for Fiber Optic Connectors

Ceramic ferrules are essential elements in fiber optic connectors. They protect and align fiber ends for reduced insertion/return losses.

Ceramic injection molding (CIM) technology is used to meet high precision requirements. Granulated nano-zirconia powder raw materials are granulated and then injected into a mold for sintering, with the blank produced being precision machined afterwards in order to meet strict performance standards.

Material

A ceramic ferrule is an indispensable element to ensure the quality and performance of fiber optic connections, from high-speed data transmission and telecom applications, to optical fiber termination using zirconia as its material. Dimensional accuracy of this component is of great significance in order to prevent loss of power transmission during data transmission processes.

Polishing procedures play a key role in ensuring the quality of ceramic ferrules. Their end must align perfectly with an optical fiber end for tight seal, reduced insertion loss and back reflection reduction. Ilsintech employs a meticulous polishing procedure with multiple inspection tools in order to produce ceramic ferrules which meet stringent standards of concentricity and dimensional accuracy.

Ground Yttrium-stabilized nano-zirconia is ground into a paste and then injected into an injection mold for sintered at high temperatures to form the ceramic ferrule. After sintereding at high temperatures, it undergoes polishing to remove machining marks, nicks, and scratches as well as measurement to classify its bore diameter into various “grades”. Choosing the appropriate grade of ceramic for any particular application is paramount to its successful performance.

Manufacturing process

Ceramic ferrules are essential elements in fiber-optic connectors. They hold the end of an optical fiber in place while precisely aligning it to its socket of the connector – without them, power may be lost during transmission.

Ceramic ferrules have many applications due to their strength, durability and resistance against harsh environments. Optic connectors that use ceramic ferrules provide low insertion loss with excellent electrical properties while offering increased wear-resistance and dimensional stability.

Up until the early 2000s, most ceramic ferrules were produced through extrusion molding. This required extruding raw material into a larger shape before cutting, polishing and hole drilling to reach final dimensions – which required many hours of laborious effort and increased the cost significantly.

Adamant Namiki engineers developed an injection molding technology that eliminates the need for drilling. Ilsintech now relies on this advanced production technique.

Injection-molding starts with specially processed yttrium-stabilized zirconia nanopowder raw materials being granulated and injected into a special mold, before being sintered at high temperature to form a ceramic ferrule blank. Precision grinding then allows the blank to achieve sub-micron processing accuracy for excellent rigidity and dimensional tolerance.

Performance

Ceramic ferrules are essential elements of optical fiber connectors. Their primary role is to support and secure conductors for maximum performance and stability of telecom devices, and enable accurate alignment between end faces of optical fibers for accurate transmission of information; quality zirconia ceramic ferrules manufactured under precise and stringent standards guarantee maximum performance.

Ferrule bore diameter must exactly correspond with that of the optical core for maximum performance, and even small variations in this tolerance can have serious repercussions for connectivity performance. Any gaps or mismatches between endfaces could lead to insertion loss which reduces light transmission capacity.

Kyocera employs numerous precision processing techniques and jigs when producing zirconia ceramic ferrules for LC/FC connectors, using them to produce high quality products with high concentricity on both ends as well as inner/outer diameter dimensions that perfectly complement optical core diameters. This ensures the ferrule has maximum optical core compatibility.

Another key consideration is achieving lateral matching between the endfaces of the ceramic ferrule and optical core, accomplished by grinding its end face, creating an 8 degree bevel on its end surface for improved physical contact between optical fiber and its cladding.

Applications

Fiber optics utilises extremely thin optical glass fibers to transmit large volumes of data quickly over long distances. Ceramic ferrules are used to connect these fibers together correctly – any mismatch can lead to data loss!

Recently, most ceramic ferrules were made of alumina. But recently, new technology has produced ceramics with much higher performance standards; specifically ceria-zirconia which provides lower Vicker’s hardness and KIC fracture toughness than alumina while providing excellent strength and thermal stability. Plus these softer ceramics polish much easier allowing better mating of an optical fiber to the ferrule.

Zirconia ceramic ferrules come in various styles to fit different connector types. They provide low insertion loss, low back reflection and superior durability over repeated matings while offering smooth taper designs to guide optical fiber into them without scratching its ends.

Ceramic ferrule manufacturing processes must meet stringent concentricity standards to avoid signal loss, since their inner diameters require precision manufacturing. If this precision is not met, an air gap could form between ceramic ferrules leading to signal degradation.