In a Passive Optical Network (PON), optical splitters play a crucial role in distributing light signals to multiple end-users. A PON is a telecommunications network that uses fiber optic cables to deliver data, voice, and video services to subscribers. The main feature of a PON is that it uses passive components, like optical splitters, to split and distribute signals without the need for active electronic devices.
Optical splitters in PONs are typically based on the principles of fused biconical taper (FBT) or planar lightwave circuits (PLC). Let's explore how each type of optical splitter works:
Fused Biconical Taper (FBT) Splitters:
FBT splitters are made by fusing two or more optical fibers together and then stretching them to create a tapered region. The taper causes the light signals to be distributed among the output fibers based on a specific splitting ratio.
Here's a simplified explanation of how FBT splitters distribute light signals:
Input: The optical signal, which contains data, enters the FBT splitter through its input fiber.
Splitting Ratio: The taper's design determines the splitting ratio, which could be, for example, 1:4, 1:8, or 1:32. This ratio indicates how the input signal will be divided among the output fibers.
Tapering: As the light propagates through the taper, the power of the signal diminishes gradually, and it is distributed to the output fibers proportionally based on the splitting ratio.
Output: The light signals exit the FBT splitter through the respective output fibers, each carrying a fraction of the original signal's power.
Planar Lightwave Circuits (PLC) Splitters:
PLC splitters use a different technology involving waveguides fabricated on a silica wafer. These waveguides are designed to split the light signals evenly according to the desired splitting ratio.
The process of distributing light signals through PLC splitters is as follows:
Input: The incoming optical signal is coupled into the PLC splitter's input port through an optical fiber.
Waveguide Splitting: Inside the PLC splitter, the optical signal passes through an intricate waveguide network designed to split the signal into multiple paths based on the splitting ratio.
Splitting Ratio: The design of the waveguide determines the splitting ratio, which can be pre-configured to any desired value.
Output: The split light signals are then directed to separate output ports, each corresponding to a specific fraction of the original input signal's power.
Both FBT and PLC splitters are widely used in PONs depending on the specific network requirements. These passive optical splitters enable the efficient distribution of optical signals to multiple subscribers without the need for active components, making PONs cost-effective and scalable solutions for high-speed broadband services.