What is the difference between PLC light division and FBT light division?

Light division technology is an important part of fiber optic communication systems. It allows multiple signals to be transmitted over a single fiber, increasing the capacity of the system. There are two types of light division technology used in fiber optic communication systems: PLC (Planar Lightwave Circuit) and FBT (Fused Biconic Taper) light division. In this article, we will discuss the differences between PLC and FBT light division.

PLC Light Division

PLC light division is a passive optical component that uses a planar waveguide to split the light into multiple channels. It is fabricated using lithographic techniques and consists of a thin layer of silica or silicon dioxide deposited on a substrate. The waveguide is patterned using a photolithographic process, which creates a series of channels that are etched into the silica layer.

PLC light division technology is highly efficient, with low insertion loss and high isolation between channels. It is also highly stable and can operate over a wide range of temperatures and wavelengths. PLC light division devices are available in various configurations, including 1x2, 1x4, 1x8, and 1x16.

FBT Light Division

FBT light division is a passive optical component that uses a fused biconic taper to split the light into multiple channels. It consists of two or more optical fibers that are fused together and tapered to create a single output fiber. The tapering process causes the light to be split between the fibers in proportion to their cross-sectional area.

FBT light division technology is relatively simple and low-cost, making it ideal for use in mass-produced components. However, it has higher insertion loss and lower isolation than PLC light division technology. FBT light division devices are available in various configurations, including 1x2, 1x4, 1x8, and 1x16.

Differences between PLC and FBT Light Division

Fabrication

PLC light division devices are fabricated using lithographic techniques, which allow for precise control over the waveguide geometry and dimensions. This results in high efficiency, low insertion loss, and high isolation between channels. FBT light division devices are fabricated by fusing and tapering optical fibers, which is a relatively simple and low-cost process. However, it results in higher insertion loss and lower isolation than PLC light division.

Wavelength Range

PLC light division devices can operate over a wide range of wavelengths, typically from 1260 nm to 1650 nm. FBT light division devices are limited to a narrower wavelength range, typically from 1310 nm to 1550 nm.

Channel Count

PLC light division devices are available in higher channel counts than FBT light division devices. PLC light division devices are available in up to 1x32 configurations, while FBT light division devices are typically limited to 1x16 configurations.

Temperature Stability

PLC light division devices are more temperature stable than FBT light division devices. This is because PLC light division devices are fabricated using materials with low thermal expansion coefficients, which results in minimal temperature-induced drift. FBT light division devices, on the other hand, are fabricated using materials with higher thermal expansion coefficients, which results in temperature-induced drift.

Size

PLC light division devices are smaller and more compact than FBT light division devices. This is because PLC light division devices are fabricated using planar waveguide technology, which allows for high channel density in a small footprint. FBT light division devices, on the other hand, require multiple fibers to be fused and tapered, which results in a larger and less compact device.