A fiber fused taper coupler (FBT Coupler, hereinafter referred to as a fiber coupler) is a passive optical device that can decompose an optical signal into multiple optical signal outputs, including one or two input ends and multiple output ends. One of the functions of fiber optic couplers is to split and combine optical signals. It is an indispensable optical element in wavelength division multiplexing, optical fiber local area network, optical fiber cable television network, interferometric optical sensor, and some measuring instruments (such as optical time domain reflectometer).
How Fiber Couplers Work?
Two (or more than two) optical fibers with the coating removed are disturbed in a certain way, melted under high temperature heating, and stretched to both sides at the same time, and finally a special waveguide structure in the form of a double cone is formed in the heating area. Controlling the twisting angle of the optical fiber and the length of stretching can obtain different coupling ratios, thereby realizing a specific function of an optical passive device.
In general, when the cores of two optical fibers are close enough, the optical signal transmitted in one optical fiber can enter the other optical fiber, that is, the optical signal can be redistributed in the two optical fibers, which is exactly The origin of fiber optic couplers.
