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Entry  Tue Sep 10 17:17:11 2019, Shalika Singh, Noise Budget, PD noise, Dark Noise measurement of Extended InGaAs  8x
    Reply  Tue Sep 10 18:38:18 2019, Koji, Noise Budget, PD noise, Dark Noise measurement of Extended InGaAs  
Message ID: 2420     Entry time: Tue Sep 10 18:38:18 2019     In reply to: 2419
Author: Koji 
Type: Noise Budget 
Category: PD noise 
Subject: Dark Noise measurement of Extended InGaAs  

- Previously, your TIA was pretty much dominated by the thermal noise current of the 5K transimpedance resistor (=0.129/sqrt(5000) nA/rtHz ~2pA/rtHz).
So, I believe it's impossible to measure 1pA/rtHz. Please check if you had any saturation or anything along the chain.

- Do you need SR560? If you think you are limited by the input noise of SR785 when having no SR560, you can use your whitening filter, which is supposed to be sufficient and better in terms of the output voltage range.

- Please note the serial number of the PD under the test.

- And, try to isolate your box from the optical table.

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