Luna does not have any particular recommendation for a switch vendor or model. The only optical requirement is that the loss and optical phase through the switch path needs to be stable while the 6415 is acquiring data. In the distance past ( 10 yrs or more ) switch stability was a concern; switch instability could cause reflection events on the far side of the switch to widen in spatial extent. We haven’t heard of customers with this issue in recent years however. Stability is less of an issue if you are buying a new switch, but if you are using an old switch and the scan results show blurred, broadened peaks, the switch could be the cause.
Customers who want to automate measurements through a switch with the 6415 will need to use software v2.2 (released in Mar 2021) or greater as the SCPI command set was introduced with v2.2. We recommend that the customer choses a switch that also supports SCPI remote control so that the 6415 and switch can be controlled through the same interface.
The main issue to be concerned about when controlling the 6415 and a switch with SCPI commands is making sure that the 6415 isn’t making an acquisition while the switch is in the process of transitioning to a different output port. The 6415 command to initiate a data trace acquisition is “init”. This should be followed up with an “opc” command to get the operational state; this command will result in a “1” being returned when the acquisition is finished and the instrument is ready to take another measurement. At this point the user is free to tell the switch to change ports; ideally the switch would have a similar state check command to tell when the switch port change is completed.