Reports until 11:56, Wednesday 09 October 2019
H1 SQZ (SQZ)
nutsinee.kijbunchoo@LIGO.ORG - posted 11:56, Wednesday 09 October 2019 (52359)
Darknoise/Shotnoise from various SQZ PDs

Daniel, Nutsinee

Yesterday we did a series of lightbulb measurement with several squeezer diodes used in OPO, CLF, SHG, and TTFSS loop. The diodes used are as follow:

SYS Diode SN DC transimpedance  RF transimpedance (measured)
SHG

BBPD S1200236

20kOhms 4.8kOhms
OPO

BBPD S1200234

2kOhms 1.55kOhms
CLF

S1900052

10kHms 25kOHms
TTFSS New Focus 1611 10kOhms 720Ohms

 

SHG diode has an RF amplifier ZFL-500LN+ (27dB gain) attached and gain a factor of 10 from the mad box gain switch.

CLF diode also has ZFL-500LN+ attached. This is the modified diode from alog47222

The SHG, OPO, and CLF diode spectrum was measured at the IMON (QMON for CLF) output. The IQ demod board gain of 5 has been included. The RF sideband folding factor of sqrt(2) has been included in OPO calculation only (high modulation depth for 80MHz sidebands). 

TTFSS New Focus 1611 Agilent spectrum came from the output of TTFSS pre-amp board. Using the pre-amp gain of 8 (+18dB) the calculated transimpedance is 720Ohms (D1700324). The spec sheet claims 700Ohms. Not bad. The measurement came in dBm/Hz. I converted dBm to V^2 using:

P(dBm) = 10log10(V^2/(R*p0))

;R = 50Ohms and p0 is a reference power 1mW

Then I sqrt(V^2/Hz) to get V/sqrt(Hz)

 

Putting everything in one place for a future reference.

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