Insertion Loss
The insertion loss of a fibre splitter is the quantities of dB lost in each output relative to the input light. Generally, the lower the insertion loss is, the better the splitter performs.
Splitting Ratio
The splitting ratio is defined as the ratio of the output power of each output port of a fibre splitter. Typically, the splitting ratio of a PLC splitter is distributed equally, while the splitting ratio of a fused tapered splitter can be unequally divided. The specific ratio is set in relation to the wavelength of the transmitted light, e.g. a splitter transmits 1.31 µm light with a splitting ratio of 50:50 at both outputs; when transmitting 1.5 µm light, it becomes 70:30 (this happens because the splitters have a certain bandwidth, i.e. the bandwidth of the transmitted optical signal when the splitting ratio is basically constant).
Isolation
Isolation is the ability of a fibre splitter to isolate the optical signal in one optical path from other paths.
Return loss
Return loss, also known as reflection loss, is the power loss of an optical signal returned or reflected by a discontinuity in the optical fibre or transmission line. The greater the return loss is,the better; to reduce the impact of reflected light on the light source and the system.
In addition, uniformity, directionality, PDL polarisation loss, etc. are also parameters that affect the performance of splitters.