The "wires" inside a fiber optic splitter are called optical waveguides or fibers, which guide and split the light signal.

Internal Structure of Fiber Optic Splitters

Inside a fiber optic splitter, the optical signal is carried and divided by waveguides, which are essentially the internal fibers or channels that direct light from the input to multiple outputs. In Fused Biconical Taper (FBT) splitters, multiple fibers are fused and tapered together so that light entering the input fiber is distributed among the output fibers through controlled coupling and interference of the cores. In Planar Lightwave Circuit (PLC) splitters, the waveguides are fabricated on a silica glass substrate using photolithography, forming precise channels that split the light evenly across multiple outputs .

Function of Waveguides

The waveguides inside the splitter operate based on total internal reflection and differences in refractive index between the core and cladding of the fiber. This ensures that the incoming optical signal is divided accurately among the output fibers, maintaining signal strength proportional to the input power . Each waveguide leads to an output port, and the number of waveguides corresponds to the number of outputs, which can range from 2 to 64 or more depending on the splitter type .

Summary

In short, the "wires" you see inside a fiber optic splitter are optical waveguides or fibers. They are the essential components that carry, guide, and split the light signal from a single input fiber to multiple output fibers, enabling efficient distribution in fiber optic networks such as FTTH and PON systems .