How does a Fiber Splitter work?

A Fiber Splitter, or Fiber Optic Splitter, works based on the principles of optics, particularly the phenomenon of total internal reflection and the properties of optical waveguides. Here's a detailed explanation of how it operates:

Basic Principles

• Optical Waveguide Structure: The splitter's internal structure is designed as an optical waveguide, which guides light through the material using total internal reflection.
• Total Internal Reflection: When light strikes the boundary between two media (such as the core and cladding of an optical fiber), it reflects back into the original medium if the angle of incidence is greater than the critical angle. This principle is crucial for maintaining the light signal within the fiber.

Working Mechanism

1. Input Signal: A high-frequency laser or optical pulse signal from an upstream network node is fed into the splitter through an input fiber.

2. Signal Distribution:

   • Fused Biconical Taper (FBT) Splitter: In this type, two or more stripped optical fibers are closely aligned and fused together under heat. They are then stretched to form a biconical taper. As light enters this taper, it begins to propagate through multiple fiber cores due to total internal reflection. At the end of the taper, the light is distributed to each output fiber according to a predetermined ratio.
   • Planar Lightwave Circuit (PLC) Splitter: PLC splitters use micro-optical processing techniques to create complex waveguide structures on a quartz substrate. Light entering the input end follows the designed waveguide path and splits into multiple signals at branching points, which are then emitted from the output ends.

3. Output Signals: The distributed light signals are transmitted through output fibers to downstream network devices or end-users.

Key Points

• Signal Attenuation: Splitting the light signal into multiple outputs results in some loss of signal strength, known as attenuation.
• Uniformity: In ideal cases, the splitter distributes the signal uniformly or according to a specified ratio among the output fibers.
• Waveguide Design: The performance of the splitter depends on the precision of the waveguide design and manufacturing process.

Applications

Fiber splitters are widely used in various scenarios such as fiber-to-the-home (FTTH), local area networks (LAN), and wireless communication base station backhaul. They are indispensable components for building fiber optic networks.

In summary, a Fiber Splitter operates by guiding and splitting light signals within an optical waveguide structure, utilizing the principles of total internal reflection and precise waveguide design.