Attenuator
A fibre attenuator takes a set share of the light, the same both ways. It brings a laser down to what a photodiode can take, or balances two arms.
Ports
Ports 1 and 2, one each side.
The model
For an attenuation \(A\) (dB),
\[\mathbf S_{12} = \mathbf S_{21} = 10^{-A/20}\,\mathbf I,\]so the power through is \(10^{-A/10}\) of what came in. The attenuation can be swept, as any setting can.
Settings
| Field | Default | Meaning |
|---|---|---|
att | 3 | Attenuation (dB) |
From the tool's own tables, file format version 1: the names are those in a .jekray file.
Assumptions
- The loss is flat in wavelength and the same for both polarisations, and adds no phase or reflection.