PLC (Planar Lightwave Circuit) splitter is an important component in PON (passive optical network) where a single optical input is split into multiple outputs. This makes it possible to deploy a Point to Multi Point physical fiber network with a single OLT (optical line terminal) port serving multiple ONTs (optical network terminal). The most common split ratios are 1:N or 2:N. N represents the output ports, usually as 2, 4, 8, 16, etc. The optical input power is distributed uniformly across all output ports. The shares the cost and bandwidth of the OLT and reduces fiber lines. This article will tell about how to keep a high quality PLC splitter from manufacturing to testing sides.
PLC splitter is composed by many miniature parts. Among them, there are three main components: fiber array for the input and output, and the chip. These three main components decide whether the PLC splitter is of good quality or not. Let’s see the key manufacturing steps of a PLC splitter.
Then how to determine the quality The GR-1209 standards provides comprehensive optical performance criteria. The following will introduce these specifications such as optical bandpass, insertion loss, return loss, uniformity and directivity.
Optical Bandpass
In a PON system, the downstream transmission uses 1490nm wavelength and 1310nm wavelength for the upstream transmission. Besides, the requirement for RF video overlay and network testing/maintenance should also be considered. The transmission wavelength for RF video is 1550 nm. And the wavelengths for networking testing and maintenance are 1550 nm and 1625 nm. So the standard opterating wavelength for a PON splitter is determined as 1260~1650 nm which covers most of the optical bands.
Uniformity
Uniformity means the maximum insertion loss value between one input port and any two output ports or between two input ports and one output port. This can ensure that the transmission power at each output port is the same in a PON system to simplify the network design.
Directivity
Directivity is the part of power transferred from one input port to another input port or from an output port to another output port. For a 2xN optical splitter, when light injects into one of the input ports, light doesn’t only propagate out of the output ports. Some of the light propagates back through the second input port. And when the light injects into one of the output ports, light propagates back through the other output ports. In a bidirectional transmission system such as a PON, directivity is useful to reduce signal crosstalk. A high directivity value will increase the insertion loss due to the optical power loss.
In FTTx and PON architectures, fiber optic splitter is an important component to share the optic network with multiple users. The basic principle of fiber optic splitter is to split one optic light beam into several parts at a certain ratio. According to different manufacture technologies, fiber optic splitters can be divided into PLC splitter and FBT Splitter. You may wonder the differences of the two splitter types when making a choice between them. This article aims at helping you to understand their distinctions and make better decisions.
What Is FBT Splitter?
FBT, or fused biconic taper uses the traditional technology to fuse several fibers together closely. Fibers are aligned by heating for a specific location and length. Fusion process will not stop until the parameters of the fibers reach the required standards. Since fused fibers are very fragile, they are protected by a glass tube made of epoxy and silica powder. Then a stainless steel tube covers the inner glass tube and is sealed by silicon.
Since their invention in the 1970s, have greatly changed the way wires and wire-dependent industries work. In the communications industry alone, fiber optic cable types have largely replaced copper wire as the primary means of signal transmission. Their use, however, spans a wide array of applications, including cable television, educational institutions, electrical utility plants, industrial companies, medical technologies, and military operations.
