Fiber optic adapter (also called coupler) is a small device that used to terminate or link the fiber optic cables or fiber optic connectors between two fiber optic lines. A fiber optic connector is a mechanical device used to align and join optical fibers, enabling light to pass through with minimal loss. Unlike fiber splicing, which is permanent, connectors allow for easy connection and disconnection of cables, making them ideal for maintenance and flexibility in. Of the more than a dozen types of fibre-optic connectors available, the four most commonly used today are LC, SC, FC, and ST.