Laser-Lock Box : suggested improvement

New Features, Requests, and Feedback
1

After working for some times with the laser lock box on fiber resonator, I have encountered some issue/drawback that I found could be improved:

  • Adding a “auto-reset” toggle for when the integrator component of the PID saturate (could be linked to the limit of the output) to automatically reset the internal of the PID. Currently, this has to be one manually from the app or with a python/matlab API but doing so prevent the use of the desktop app. This feature could also be useful in the PID/LIA instrument but make even more sense when locking onto cavity due to the cyclical nature of the signal.

  • If often found that the integrator component of the PID is not optimal for cavity setup as its delicate balance in the kHz range where a strong I component cause instability but in the sub Hz range the same I component is too weak to correct for the perturbations. Adding double integrator has the opposite issue where it’s too strong at lower frequency and causes saturation of the PID.
    This recent paper : https://journals.aps.org/prd/abstract/10.1103/PhysRevD.110.062004 uses a fractional integrator implemented in the MCC for the stabilisation of a laser cavity for the LISA. Adding such fractional in the Laser Lock-Box/PID (with either slope 1/2 or 3/2) could be useful for high precision stabilisation.

Thanks in advance for the support

2

Thank you for the feature request, I have created a ticket for our dev team.

3

Hi @Azercoco, thank you for your feedback and I am happy you have read my paper!! We are considering fractional integrator as a feature for the PID but we do not have a timeline for it now. If you are interested in the fractional integrator for your setup, I can assist you using MCC.