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Entry  Mon Jun 9 10:55:48 2014, Nichin, Summary, Electronics, BBPD D1002969-v8 transimpedence measurement PD_transimpedence_measurement.pngresults.pdfcode_and_data.zip
    Reply  Mon Jun 9 16:55:31 2014, Koji, Summary, Electronics, BBPD D1002969-v8 transimpedence measurement 
Message ID: 10009     Entry time: Mon Jun 9 10:55:48 2014     Reply to this: 10012
Author: Nichin 
Type: Summary 
Category: Electronics 
Subject: BBPD D1002969-v8 transimpedence measurement 

My SURF week-1 work...

Motivation:

To measure the transimpedence of  the Broadband photodiode (D1002969-v8), using a New focus photodiode (1611) as reference. The amplitude modulated Jenne Laser (1.2mW) was used. 

The steps involved in getting the transimpedence are as follows:

Acquiring data

  • Get 2 sets of data from Network Analyzer Agilent 4395: One set of data will be for the transfer function of Ref PD over RF out. The other set for Test PD over Ref PD.
  • The following conditions were set:

1) Frequency sweep range: 1MHz to 200 MHz.

2) Number of Points sampled in  the range: 201

3) Type of sweep: Logarithmic

  • Set the NA to give the corresponding transfer function values in dB and also Phase response in degrees.
  • Save the data into floppy disk for processing on the computer (The wireless way of acquiring data was not working when the experiment was conducted )

Plotting

  • The matlab code attached (TransimpedencePlot.m) will then give plots for the absolute values of transimpedence in V/A.
  • Logic involved in the code:
    • Transimpedence = Voltage response / (Responsivity of the photodiode * Power incident) 
    • Responsivity for BBPD is taken as 0.1 A/W and for NF1611 as 0.68 A/W as given in their datasheets.
    • Voltage response of Test PD w.r.t RF output of NA (in dB) = Voltage response of Test PD w.r.t Ref PD (in dB) + Voltage response of Ref PD w.r.t RF output of NA (in dB) 

 Results

The Plots of transimpedence obtained are attached (results.pdf) . The results obtained for BBPD is consistent with the ones obtained before, but the same method and code gives a different transimpedence for 1611.

The transimpedence of NF 1611 was obtained to be around 4-5 V/A which is very much off-track compared to the one given in the datasheet (elog: 2906).

 

The transimpedence of  Broadband photodiode (D1002969-v8) was around 1200 - 1300 V/A for most of the range, but the value started falling as the frequency approached 100 MHz. This result is consistent with DCC document: T1100467-v2.

 

Attachment 1: PD_transimpedence_measurement.png  21 kB  | Hide | Hide all
PD_transimpedence_measurement.png
Attachment 2: results.pdf  117 kB  Uploaded Mon Jun 9 13:16:11 2014  | Hide | Hide all
results.pdf results.pdf
Attachment 3: code_and_data.zip  19 kB  Uploaded Mon Jun 9 14:01:43 2014
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