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R&D (FilterCavity)
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YaoChinHuang - 01:04, Saturday 30 November 2019 (1904)Get code to link to this report
IR light jitter on LO & FC path

Yao-Chin and Yuhang

 

When IRMC locking, we monitored yaw & pitch of LO light jittering by position sensitive detector(PSD) as shown in fig 1. PSD was put before alignment mode cavity(AMC). We also measured yaw & pitch of PSD dark noise.

In addition, we sent 200mV Vpp of random noise to IR phase shifter(IRPS) and measured again yaw & pitch of LO light jittering as shown in fig 2. Magnitude value increased more obviously above 60Hz than without random noise situation.

When BAB light sent to filter cavity, we monitored yaw & pitch of reflect light by PSD as shown in fig 3. Because suspension mirror jittering, The jittering magnitude of low frequency range (<200Hz for yaw, <500Hz for pitch) is huge.

Images attached to this report
1904_20191129163406_figure1.png 1904_20191129163426_figure2.png 1904_20191129163437_figure3.png