[Katrin / Kiwamu]
The beat-note between the PSL green laser and the Y end green laser was successfully detected.
The detection was done by the new broad-band RFPD.
The next step will be an extraction of the frequency fluctuation signal using the delay-line-mixer frequency discriminator.
(What we did)
+ Connected a BNC cable which goes from the c1iscey's DAC to the laser slow input
=> this enables a remote control of the laser frequency via the temeperature actuation
+ Realigned the beam pointing of the Y end green laser
+ Installed all the necessary optics on the PSL table
=> currently the PSL green light is adjusted to completely S-polarization
+ readjusted the mode matching telescopes
=> the Y green beam becomes the one with a long Rayleigh range
+ Health check on the broad-band RFPD to see if it is working
+ Installed the BB-RFPD with a +/-15V power supply
+ Fine alignment of the beam combining path
+ Fine tuning of the Y end laser temperature
=> T_PSL = 31.72 deg when the slow FSS feedback is zero.
=> Based on Bryan's measurement (see #elog) the Y end laser temperature was adjusted to 34.0 deg by applying an offset to the slow input.
+ Found the beat note at 100 MHz or so.
=> optimizing the alignment of the beam combining path by maximizing the peak height of the beat-note.
=> maximum peak height observed with an RF spectrum analyzer was about -36 dBm.