A planar waveguide optical splitter (PLC splitter) divides a single optical signal into multiple outputs using silica-based waveguides on a planar substrate, relying on total internal reflection and precise waveguide branching.

Working Principle

A PLC splitter operates as a passive optical device that distributes light from one or two input fibers to multiple output fibers with high uniformity and low loss . The core principle is based on planar waveguide technology, where optical signals propagate through silica waveguides fabricated on a flat substrate using photolithography techniques adapted from semiconductor manufacturing .

1. Launching: The incoming optical signal from the input fiber is coupled into the input waveguide on the PLC chip.
2. Propagation: Light travels through the waveguides via total internal reflection, maintaining signal integrity.
3. Splitting: The waveguides branch symmetrically in Y-shaped or cross-shaped patterns, dividing the optical power evenly across multiple paths.
4. Output: The split signals exit through the output waveguides and fibers, each carrying a fraction of the original optical power .

Structure

A PLC splitter consists of:

• A planar waveguide chip made of silica glass.
• Input and output waveguide arrays coupled to the chip.
• Optional packaging types such as bare fiber, ABS, LGX, or rack-mount configurations depending on deployment needs . The number of output ports (e.g., 1x4, 1x8, 1x32, 1x64) determines the splitting ratio, and the design ensures uniform optical power distribution across all outputs .

Advantages

Compared to traditional FBT (Fused Biconical Taper) splitters, PLC splitters offer:

• High splitting accuracy and uniformity.
• Low insertion loss.
• Compact size suitable for large-scale optical networks.
• Scalability for high port counts, making them ideal for FTTH and PON networks .

Applications

PLC splitters are widely used in passive optical networks (PON), including EPON, GPON, and BPON, to connect central office equipment to multiple end users. They can be deployed in centralized architectures (e.g., 1x32 at the central office) or distributed architectures (e.g., 1x4 near the OLT followed by 1x8 at terminal enclosures), . In summary, the planar waveguide optical splitter leverages precise waveguide design and branching to efficiently split optical signals, providing a reliable, scalable, and low-loss solution for modern fiber-optic communication networks .