[Doug Cook, Suresh Doravari]

This is with reference to the  alog 14902 which described the 100% power drop outs in diode laser unit 199 .  Though I managed to stop it from those power drop outs, it turned out that the temperature servo is somehow broken in this laser.  The long duration trend below shows that the power never quite reaches a stable operating  point even after several days.   Consequently the laser does not stop glitching either.

We fixed unit 130-1 and plugged it  into HAM3 oplev.   This laser did not require any fiber port alignments.  We just adjusted the T setpoint to shift its stable operating power.  1.12V (unscaled temperature indicator) to 1.03V.

This unit is currently operating in HAM3 oplev for the past few days and its performance is good.  There have been no glitches since we plugged it in and chose an appropriate operating power.   The plot attached shows 6 hour stretches over 24 hours. 

The Pitch Sum and Yaw spectrogram shows that even though there are no glitches in the laser power output (Sum signal) the Pitch and Yaw signals show glitches.  Which indicates table motion or perhaps pier motion. This requires further investigation.

The spectra of HAM3 oplev is posted chiefly to show that the gain and whitening currently set are adequate to raise the signal above the ADC noise.