.
Ref.
10K鈩?/div>
Calibration
Adjustment
The pigtailed photodiode and DN135 assembly
is calibrated by introducing an optical signal of
known magnitude into the fiber and adjusting
the calibration potentiometer so that the output
voltage corresponds to the input power level.
Example:
One hundred microwatts of optical power
@1550nm is introduced into a fiber that is
terminated in an InGaAs photodiode.* Adjust
the calibration control shown in Figure 1 until
the output voltage indicates 3.500 Volts. The
optical power monitor is now calibrated at
1550nm.
The calibration control can be driven from an
external voltage source such as the output of a
digital to analog converter. This would allow
the power monitor to be automatically
calibrated in a systems application.
*A typical InGaAs photodiode may have a
responsivity of 0.9mA/mWatt of optical power
at 1550nm. This would provide an output of
current of 90碌A(chǔ) with an input power of 100碌W.
The calibration control corrects for variations in
the responsivity of various photo diodes.
鈩?/div>
6.81K鈩?/div>
INPUT
CURRENT
Amperes
1
100
10
1
100
10
1
100
mA
碌
A
碌
A
碌
A
nA
nA
nA
pA
OUTPUT
VOLTAGE
Volts
4.000
3.500
3.000
2.500
2.000
1.500
1.000
0.500
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