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Entry  Wed Nov 18 16:58:36 2009, kiwamu, Update, Electronics, multi-resonant EOM --- EOM characterization --- EOM_impedance.png
    Reply  Wed Nov 18 22:38:17 2009, Koji, Update, Electronics, multi-resonant EOM --- EOM characterization --- 
Message ID: 2294     Entry time: Wed Nov 18 16:58:36 2009     Reply to this: 2295
Author: kiwamu 
Type: Update 
Category: Electronics 
Subject: multi-resonant EOM --- EOM characterization --- 

In designing the whole circuit it is better to know the characteristic of the EOM.

I made impedance measurement with the EOM (New Focus model 4064) and I found it has capacitance of 10pF.

This is good agreement with the data sheet which says "5-10pF".

The measured plot is attached below. For comparison there also plotted "open" and "10pF mica".

In the interested band( from 1MHz to 100MHz), EOM looks just a capacitor.

But indeed it has lead inductance of 12nH, resistance of 0.74[Ohm], and parasitic capacitance of 5.5pF.

In some case we have to take account of those parasites in designing.

EOM_impedance.png

 

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