Elli. Greg. Aidan. Nutsinee.

The HWSY SLED has ended it's useful lifespan. The power has decayed by about 90% as shown in the attached plot of the last 6 months.

This is due to running it consistently at a high current. At present, there is a hardware maximum current limit on the SLED driver (https://dcc.ligo.org/LIGO-T1000662) which has been set to the maximum limit specified by the SLED supplier (it's also unqiue for every diode). I think we need to set this limit lower to increase the lifetime of these SLEDs - we always wanted to run them at roughly half the output power, but this has control has been hanlded in software.