Lab entry
in: Wed Oct 28 18:11:00 2020
out: Wed Oct 28 21:05:58 2020
E laser noise
- Moved the Newfocus 1611 from W path cryo cantilevers transmission, to just after the PSOMA beam launch.
- nominal AC gain: 700 V/A
- nominal DC gain: 10 kV/A
- output impedance: 50 Ohm
- Max input power: 1 mW DC (10 mW CW)
- Measuring the following spectra across the PD band (~30kHz-1GHz) by connecting the 1611 AC output directly to an HP 8560E (50 Ohm input). I'm monitoring DC with TDS3024B oscilloscope (1 MOhm input).
- dark current
- free running E path laser intensity noise
Optical layout: beam launch -> lambda/2 -> steering mirrors -> lens 1 -> ND 0.6 -> lens 2 -> PD 1611
There is only a 12 VDC power supply compatible with the 1611 power port, but the PD requires +- 15V. Surely there's one somewhere. Perhaps this is why I observe only -6 V on the DC mon with 1mW input power at 1550nm (checked against the Thorlabs S122C; I expected -10V). Maybe the beam is too large. |