Coupling is the process of transferring light from one object to another. It is commonly used in optical fiber cables, which are made up of thin strands of glass that are capable of transmitting light. Coupling is the process of taking light from one cable and transferring it to another. This is done by either connecting the two cables directly, or by using an optical coupler.

When connecting two cables directly, the light is transferred through an optical connector. This connector is designed to align the two cables and ensure that the light is transferred with minimal losses. This can be done with a variety of connectors, such as a simple patch cord, or a more complex optical splice.

When using an optical coupler, the light is transferred from one cable to another through the use of a device that is specifically designed to do this. These devices can be mechanical or optical, depending on the type of connection that is being made. For example, a mechanical coupler will mechanically align the two cables, while an optical coupler will use an array of lenses and mirrors to transfer the light.

No matter how the light is transferred, the overall process of coupling is designed to ensure that the light is transferred with minimal losses. This is important because it allows for the transmission of large amounts of data over long distances with minimal signal loss. Coupling is also used in many other applications, such as in fiber-optic communication systems and in optical sensors.