What are the two components of an optical coupler

An optical coupler is a device used to transmit optical signals between fibers or to split/merge light signals in fiber-optic systems. The two fundamental components are:

1. Light Source (Emitter) This component generates the optical signal, typically in the form of photons. It can be a laser diode or an LED, depending on the application. The light source converts electrical signals into optical signals that can travel through the fiber.
2. Light Receiver (Detector) The receiver absorbs the optical signal transmitted through the fiber and converts it back into an electrical signal. This ensures that the transmitted information can be processed or measured at the output end. These two components are housed in a single casing and are isolated from each other by a transparent insulator to prevent interference while allowing efficient light transmission. The coupler ensures that light from the source is effectively coupled into the receiving fiber, enabling signal splitting, combining, or extension of optical links in telecommunication networks, cable TV systems, and local area networks .

Optical couplers can also be implemented using fiber fusion techniques, where multiple fibers are twisted, stretched, and fused together so that their cores are in close contact. This allows light to transfer between fibers via evanescent wave coupling, which is common in passive fiber-optic couplers . While the basic components remain the light source and receiver, the physical implementation may vary depending on whether the coupler is a fused fiber type, planar lightwave circuit, or bulk-optics-based device.