Operation
MXFS
A05595_02_E00_00
HBM: public
37
Wavelength shift due to sweeping laser speed in MXFS
Δλ
+
2
@
1.446
@
104
0.84
@
3
@
10
8
@
d
@
RepRate
+
1.1585
@
10
*
6
@
d
@
RepRate
Next tables aim to illustrate the difference in a sensor readout (wavelength shift
in pm) caused by the distance between the Interrogator and the sensor for the
different devices and options.
Distance (m)
Acquisition rate (Hz)
100
2000
10
1.2
23.2
50
5.8
115.9
100
11.6
231.7
150
17.4
347.6
200
23.2
463.4
500
57.9
1158.5
1000
115.9
2317.0
1500
173.8
3475.5
2000
231.7
4634.1
5000
579.3
11585.1
Tab. 3.1
Shift in wavelength (pm)
Distance compensation
The distance compensation is advised for optical sensor measurements where
the two below conditions are true:
S
The pair distance/acquisition rate causes an error bigger that the
interrogator´s “accuracy”;
S
The measurement is based on an absolute wavelength measurement,
which is true for the temperature sensors only. The remaining sensor
measurements are based either on a variation of wavelength to a reference
value or on two FBG that are very close to each other.
