ST* Fiber Optic Connectors shall be compatible with TIA FOCIS-2. 5mm ferrules and have typical insertion loss of 0. 20dB (singlemode) per connector. Mouser offers inventory, pricing, & datasheets for Multimode ST Connectors Fiber Optic Connectors. The optical fiber connector is a kind of detachable passive optical component used in the connection between fiber to fiber, the light source to the fiber, and fiber to the detector to achieve the light maximize coupling to the receiving fiber.