Optical couplers, optical splitter, and optical combiner are optical devices belonging to fiber optic couplers. Optical splitters are usually Y couplers, T couplers, or tree couplers that have only one input port and two or more output ports. 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. The different types of couplers, including FBT couplers, PLC couplers, and WDM couplers, are used in a variety of applications, including optical networks, optical devices, and optical measurement and testing.