Basic Structure of Optical Splitter

An optical splitter is a passive device that divides a single optical signal into multiple outputs using either Fused Biconical Taper (FBT) or Planar Lightwave Circuit (PLC) waveguide structures.

Core Structure

Optical splitters are integrated waveguide devices that can split an incident light beam into two or more beams, containing multiple input and output ends. The main components include: Input fiber(s): One or two fibers that carry the incoming optical signal. Waveguide region: The core area where light is divided.

In FB

T splitters, this is formed by fusing and tapering fibers to create a double-cone structure.

In PL

C splitters, optical waveguides are fabricated on a silica or semiconductor substrate using photolithography. Output fibers: Multiple fibers that carry the split optical signals to end devices. Housing: Provides mechanical protection but does not affect optical performance.

Types of Splitters

Fused Biconical Taper (FBT) SplittersConstructed by removing the coating of two fibers, fusing them, and stretching under heat to form a tapered double-cone waveguide. The splitting ratio is controlled by the fiber torsion angle and stretch length. Advantages: Low cost, adjustable split ratio.

Limitations: Wavelength-dependent losses, poor spectral uniformity, and temperature sensitivity. Planar Lightwave Circuit (PLC) SplittersUses photolithographically fabricated waveguides on a silica or semiconductor substrate. Light is routed through the waveguides to achieve precise and uniform splitting.

Advantages: Wavelength-insensitive, high spectral uniformity, compact, suitable for large splits (1x32, 1x64). Limitations: More complex fabrication process.

Split Ratios and Configurations

Splitters can have equal or unequal output power. Common configurations include 1x2, 1x4, 1x8, 1x16, 1x32, and 1x64. Balanced splitters (2xN) have two inputs and N outputs, often used for redundancy.

The optical power is divided according to the split ratio, with each output receiving a fraction of the input signal.

Mini-

Module PLC Splitters

Compact PLC-based splitters designed for minimal space usage. The splitting occurs entirely within the PLC waveguide, while the external housing provides protection. They maintain flat spectral response across standard PON operating bands (1260–1650 nm) and exhibit minimal intrinsic loss.

Summary

The structure of an optical splitter combines input fibers, a waveguide splitting region, and output fibers within a protective housing. The choice between FBT and PLC technologies depends on the required split ratio, spectral uniformity, and network scale. Splitters are essential in passive optical networks (PONs), enabling a single optical line to serve multiple subscribers efficiently.