Everything about Fiber Optic Connectors

Updated: Jul 23

Standards for Fiber Optic Connectors

As an optical component, fiber optic connectors comply with several standards in telecommunications cabling or electrical engineering fields. Here is a table that provides part of the standards that fiber optic connectors accord with:

Fiber Optic Connector Definition

Fiber optic connector, or optical fiber connector, is a component to terminate the end of a fiber optic cable and enables quicker connection and disconnection than fiber splicing. It mechanically couples and aligns the fiber cores to make light pass successfully. Therefore, fiber optic connectors have an important impact on the fiber optic transmission reliability and the performance of the system. Normally speaking, high-quality optical connectors will lose very little light due to the reflection or misalignment of the fibers.

Structure of Fiber Optic Connectors

For an optical connector design, there are five key and important components: the fiber ferrule, the sub-assembly body, the connector housing, the fiber cable, and the stress relief boot. We'll take an SC connector for example to illustrate the structure of the fiber optic connector.

  • Fiber Ferrule The SC connector is built around a long cylindrical 2.5mm diameter ferrule, made of ceramic (zirconia) or metal (stainless alloy). A 124um-127um diameter high precision hole is drilled in the center of the ferrule, where stripped bare fiber is inserted through and usually bonded by epoxy or adhesive. The end of the fiber is at the end of the ferrule, where it is typically polished smooth.

  • Sub-assembly Body The ferrule will be assembled in the SC sub-assembly body that has mechanisms to hold the cable and fiber in place. The end of the ferrule is out of the sub-assembly body in order to mate with another SC connector inside a mating sleeve (i.e. adapter or coupler).

  • Connector Housing Then the connector housing will cover the connector sub-assembly body, which provides the mechanism for snapping into a mating sleeve (adapter) and holding the connector in place.

  • Fiber Cable Fiber cable and strength member (aramid yarn or Kevlar) are crimped onto the connector sub-assembly body with a crimp eyelet, increasing the strength of the mechanical handling of the connector while protecting the fiber inside at the same time.

  • Stress Relief Boot Stress relief boot covers the joint between the connector body and fiber cable to protect the fiber cable from mechanical damage. Stress relief boot designs are different for 900um tight-buffered fiber and 1.6mm-3mm fiber cable.

Key Features of Fiber Optic Connectors

The key characteristics of the fiber connectors include optical properties, interchangeability, repeatability, reliability, insertion times, etc.

  • Optical Properties: insertion loss and return loss are the two main parameters for the optical properties. The lower the insertion loss value, the better. Normally, a qualified connector should keep the inse