PLC Splitter

A PLC splitter consists of optical waveguides patterned lithographically onto a silica (glass) substrate. Light entering the input is divided equally through branches on the chip into power-of-two ratios such as 1:2, 1:4, 1:8, 1:16, 1:32 or 1:64. Needing no power, it is a basic building block of passive optical networks such as GPON and XGS-PON. It also works in reverse, combining subscriber signals onto a single fiber.

Splitting costs power. Ideally each two-way split is 3 dB, and with manufacturing losses typical insertion loss is around 3.7 dB for 1:2, 7.3 dB for 1:4, 10.5 dB for 1:8, 13.7 dB for 1:16, 17.1 dB for 1:32 and 20.5 dB for 1:64. Exact figures must come from the vendor datasheet, and the worst-case value should be used in the optical budget.

PLC splitters are largely wavelength-independent across 1260–1650 nm, so they can carry GPON, XGS-PON and RF video wavelengths simultaneously. Older, cheaper FBT (Fused Biconical Taper) splitters are more wavelength-sensitive but are still used when asymmetric ratios such as 10/90 are required.

Products come in bare-fiber, blockless (mini tube), ABS box, LGX cassette and rack-mount packages, usually with SC/APC connectors. Designs may use centralised splitting (a single 1:32 stage) or cascaded splitting (for example 1:4 followed by 1:8). Cascading saves fiber but complicates troubleshooting and budget calculations. Splitters are typically housed in splice closures or fiber distribution boxes.