¶ Light Modulation
Description:
Light modulation glitches often look like several bright spikes in close succession with low frequency noise at the same time and after the bright spikes. This glitch predominantly occurred at LIGO Hanford during the first observing run (O1) due to amplitude fluctuations in the signal used to generate the 45 MHz optical sidebands (used to control LIGO's mirrors).
These glitches have not occurred at a high rate in the third observing run (O3) and beyond. Some very different-looking glitches from O3, though, may have been caused by other malfunctions of the modulation subsystem.
Cause:
Amplitude fluctuations in the signal used to generate the 45 MHz optical sidebands.
Status:
Likely extinct.
Examples:
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Audio Example:
Make sure to wear good headphones!
More Information:
- For more information on light modulation glitches, see page 14 and Appendix A of this paper