A fiber optic coupler is a passive optical device that connects three or more fiber ends, dividing one input optical signal into two or more outputs, or combining multiple signals into one. Unlike active devices like switches or transceivers, couplers require no electrical power to. Fiber couplers belong to the basic components of many fiber-optic setups. They play a crucial role in various applications, such as telecommunications, data centers, and fiber-to-the-home (FTTH) installations.