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Entry  Sat Nov 21 13:58:30 2020, Koji, Electronics, Characterization, Dark Current Measurement for InGaAs QPDs Q3000_dark_current.pdf
    Reply  Sun Nov 22 13:49:12 2020, Koji, Electronics, Characterization, Impedance Measurement for InGaAs QPDs impedance_measurement.pdfP_20201121_183830.jpgimpedance_test.pdfQ3000_impedance_test.pdf
       Reply  Mon Nov 23 23:17:19 2020, Koji, Electronics, Characterization, The dark noise of the Q3000 QPDs Q3000_dark_noise_81.pdfQ3000_dark_noise_82.pdfQ3000_dark_noise_83.pdfQ3000_dark_noise_84.pdf
          Reply  Tue Nov 24 10:45:07 2020, gautam, Electronics, Characterization, The dark noise of the Q3000 QPDs 
             Reply  Tue Nov 24 12:27:18 2020, Koji, Electronics, Characterization, The dark noise of the Q3000 QPDs 
Message ID: 404     Entry time: Mon Nov 23 23:17:19 2020     In reply to: 403     Reply to this: 405
Author: Koji 
Type: Electronics 
Category: Characterization 
Subject: The dark noise of the Q3000 QPDs 

The dark noise levels of the four Q3000 QPDs were measured with FEMTO DLPCA200 low noise transimpedance amp.

The measurement has been done in the audio frequency band. The amp gain was 10^7 V/A. The reverse bias was set to be 5V and the DC output of the amplifier was ~40mV which corresponds to the dark current of 4nA. It is consistent with the dark current measurement.

The measured floor level of the dark current was below the shot noise level for the DC current of 0.1mA (i.e. 6pA/rtHz).
No anomalous behavior was found with the QPDs.

Note that there is a difference in the level of the power line noise between the QPDs. The large part of the line noises was due to the noise coupling from a soldering iron right next to the measurement setup, although the switch of the iron was off. I've noticed this noise during the measurement sets for QPD #83. Then the iron was disconnected from the AC tap.

Attachment 1: Q3000_dark_noise_81.pdf  963 kB  | Hide | Hide all | Show all
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Attachment 3: Q3000_dark_noise_83.pdf  961 kB  | Hide | Hide all | Show all
Attachment 4: Q3000_dark_noise_84.pdf  948 kB  | Hide | Hide all | Show all
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