Readouts are a new component in Finesse 3 which combine together both a detector and an optical component. In essence, they represent a photodetector or some other measurement device that produces an electronic signal. Therefore readout components will always have one or more optical ports which generate some electrical signal which is outputted at one or more electronic ports. These components are typically used for computing transfer functions or AC models of closed loop systems, where the electrical output can be filtered and then fed back into another component.

DC readout

readout_dc name optical_node=none pdtype=none output_detectors=false

RF photodetector readout

readout_rf name optical_node=none f=none phase=0 output_detectors=false pdtype=none