Keysight Technologies N4373D, User Manual

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Measurement Concepts
Keysight
N4373D Lightwave Component Analyzer, User’s Guide 53
OE measurements (photodiodes)
The measurement process for OE devices is similar to EO
devices. The measurement consists of the ratio of output
electrical modulation current to input optical modulation
power. Slope responsivity for OE devices describes how a
change in optical power produces a change in electrical current.
Graphically this is shown in the figure below.
The LCA measures the input optical modulation power and
output modulation current and displays the ratio of the two in
Amps/Watt.
OO measurements
Characteristics of purely optical devices can also be measured.
In this case, both the stimulus and response are modulated
light. The ratio measurement is simply one of gain or loss versus
modulation frequency.
As the lightwave component analyzer is able to measure
amplitude and phase, dispersion measurements can be made
with very high frequency resolution. This can be used to
characterize narrowband optical components with a very high
frequency resolution within the modulation bandwidth.
I
out

mA
P
in
mW
Responsivity R
r
A W
  

I
out
P
in

--------------
=
R
r
dB
 
20log
10
R
r
A W
  
A W

----------------------------
=