# Instrumentation & Measurement Magazine 24-5 - 13

```If we assume an emitting light with enough of a small spot-size
on the diaphragm center relative to the overall area of it, one
can approximate the diaphragm as a spherical convex mirror
which can reflect this beam to the receiving area of RF.
Fig. 1. Schematic diagram of a double-clad reflective-diaphragm fiber-optic
Pressure Sensor (DFOPS).
Sensor Structures and Modeling
Fig. 1 shows the designed DFOP sensor schematically. It
consists of a double-clad fiber optic probe and a flexible diaphragm
considered in contact with a uniform and smooth
pressure like a stationary fluid in a vessel. The double-clad fiber
has to be set in a way that the diaphragm initial distance
h0
.
Imposing any pressure will lead to a tiny displacement of the
central areas of the diaphragm and the output power increases.
Diaphragm Deflection Model and Analysis
The physical diaphragm deflection model was both experimentally
and theoretically analyzed [24]. The resistance of the
diaphragm against the bending caused by uniform pressure,
for thin plates gives small deflections by:
Yr 
 Db
,1
64
 

 br
4 2



where  shows the applied uniform pressure, and b and r are
Also, flexural rigidity D is:
D 
provides the minimum of receiving power by the receiving
fiber (RF), and therefore the maximum of deflection corresponds
to the maximum received power for a basic distance hb
Et
12 1 
2

3
(2)
where t, ν, and E are plate thickness, poisson's ratio, and
Young's modulus of the diaphragm, respectively [27]. Notice
that the pressure here actually means the pressure difference
relative to the other side of the diaphragm which is usually
considered as the atmospheric pressure.
2
(1)
Fig. 2. (a) The radial coordinate of diaphragm deflections versus a maximum pressure of p=1 atm for various diaphragm radiuses b(mm) when its thickness is
t=0.2 mm, and (b) their corresponding central maximum deflections versus pressure. (c) The radial coordinate of diaphragm deflections versus a maximum pressure
of p=1 atm for various diaphragm thicknesses t(mm) when its radius is b=15 mm, and (d) their corresponding central maximum deflections versus pressure. (All for
a Silicon-Nitride diaphragm: E=300 GPa; v = 0.24).
August 2021
IEEE Instrumentation & Measurement Magazine
13
```

# Instrumentation & Measurement Magazine 24-5

No label
Instrumentation & Measurement Magazine 24-5 - No label
Instrumentation & Measurement Magazine 24-5 - Cover2
Instrumentation & Measurement Magazine 24-5 - 1
Instrumentation & Measurement Magazine 24-5 - 2
Instrumentation & Measurement Magazine 24-5 - 3
Instrumentation & Measurement Magazine 24-5 - 4
Instrumentation & Measurement Magazine 24-5 - 5
Instrumentation & Measurement Magazine 24-5 - 6
Instrumentation & Measurement Magazine 24-5 - 7
Instrumentation & Measurement Magazine 24-5 - 8
Instrumentation & Measurement Magazine 24-5 - 9
Instrumentation & Measurement Magazine 24-5 - 10
Instrumentation & Measurement Magazine 24-5 - 11
Instrumentation & Measurement Magazine 24-5 - 12
Instrumentation & Measurement Magazine 24-5 - 13
Instrumentation & Measurement Magazine 24-5 - 14
Instrumentation & Measurement Magazine 24-5 - 15
Instrumentation & Measurement Magazine 24-5 - 16
Instrumentation & Measurement Magazine 24-5 - 17
Instrumentation & Measurement Magazine 24-5 - 18
Instrumentation & Measurement Magazine 24-5 - 19
Instrumentation & Measurement Magazine 24-5 - 20
Instrumentation & Measurement Magazine 24-5 - 21
Instrumentation & Measurement Magazine 24-5 - 22
Instrumentation & Measurement Magazine 24-5 - 23
Instrumentation & Measurement Magazine 24-5 - 24
Instrumentation & Measurement Magazine 24-5 - 25
Instrumentation & Measurement Magazine 24-5 - 26
Instrumentation & Measurement Magazine 24-5 - 27
Instrumentation & Measurement Magazine 24-5 - 28
Instrumentation & Measurement Magazine 24-5 - 29
Instrumentation & Measurement Magazine 24-5 - 30
Instrumentation & Measurement Magazine 24-5 - 31
Instrumentation & Measurement Magazine 24-5 - 32
Instrumentation & Measurement Magazine 24-5 - 33
Instrumentation & Measurement Magazine 24-5 - 34
Instrumentation & Measurement Magazine 24-5 - 35
Instrumentation & Measurement Magazine 24-5 - 36
Instrumentation & Measurement Magazine 24-5 - 37
Instrumentation & Measurement Magazine 24-5 - 38
Instrumentation & Measurement Magazine 24-5 - 39
Instrumentation & Measurement Magazine 24-5 - 40
Instrumentation & Measurement Magazine 24-5 - 41
Instrumentation & Measurement Magazine 24-5 - 42
Instrumentation & Measurement Magazine 24-5 - 43
Instrumentation & Measurement Magazine 24-5 - 44
Instrumentation & Measurement Magazine 24-5 - 45
Instrumentation & Measurement Magazine 24-5 - 46
Instrumentation & Measurement Magazine 24-5 - 47
Instrumentation & Measurement Magazine 24-5 - 48
Instrumentation & Measurement Magazine 24-5 - 49
Instrumentation & Measurement Magazine 24-5 - 50
Instrumentation & Measurement Magazine 24-5 - 51
Instrumentation & Measurement Magazine 24-5 - 52
Instrumentation & Measurement Magazine 24-5 - 53
Instrumentation & Measurement Magazine 24-5 - 54
Instrumentation & Measurement Magazine 24-5 - 55
Instrumentation & Measurement Magazine 24-5 - 56
Instrumentation & Measurement Magazine 24-5 - 57
Instrumentation & Measurement Magazine 24-5 - 58
Instrumentation & Measurement Magazine 24-5 - 59
Instrumentation & Measurement Magazine 24-5 - 60
Instrumentation & Measurement Magazine 24-5 - 61
Instrumentation & Measurement Magazine 24-5 - 62
Instrumentation & Measurement Magazine 24-5 - 63
Instrumentation & Measurement Magazine 24-5 - 64
Instrumentation & Measurement Magazine 24-5 - 65
Instrumentation & Measurement Magazine 24-5 - 66
Instrumentation & Measurement Magazine 24-5 - 67
Instrumentation & Measurement Magazine 24-5 - 68
Instrumentation & Measurement Magazine 24-5 - 69
Instrumentation & Measurement Magazine 24-5 - 70
Instrumentation & Measurement Magazine 24-5 - 71
Instrumentation & Measurement Magazine 24-5 - 72
Instrumentation & Measurement Magazine 24-5 - 73
Instrumentation & Measurement Magazine 24-5 - 74
Instrumentation & Measurement Magazine 24-5 - 75
Instrumentation & Measurement Magazine 24-5 - 76
Instrumentation & Measurement Magazine 24-5 - 77
Instrumentation & Measurement Magazine 24-5 - 78
Instrumentation & Measurement Magazine 24-5 - 79
Instrumentation & Measurement Magazine 24-5 - 80
Instrumentation & Measurement Magazine 24-5 - 81
Instrumentation & Measurement Magazine 24-5 - 82
Instrumentation & Measurement Magazine 24-5 - 83
Instrumentation & Measurement Magazine 24-5 - 84
Instrumentation & Measurement Magazine 24-5 - 85
Instrumentation & Measurement Magazine 24-5 - 86
Instrumentation & Measurement Magazine 24-5 - 87
Instrumentation & Measurement Magazine 24-5 - 88
Instrumentation & Measurement Magazine 24-5 - Cover3
Instrumentation & Measurement Magazine 24-5 - Cover4
https://www.nxtbook.com/allen/iamm/26-6
https://www.nxtbook.com/allen/iamm/26-5
https://www.nxtbook.com/allen/iamm/26-4
https://www.nxtbook.com/allen/iamm/26-3
https://www.nxtbook.com/allen/iamm/26-2
https://www.nxtbook.com/allen/iamm/26-1
https://www.nxtbook.com/allen/iamm/25-9
https://www.nxtbook.com/allen/iamm/25-8
https://www.nxtbook.com/allen/iamm/25-7
https://www.nxtbook.com/allen/iamm/25-6
https://www.nxtbook.com/allen/iamm/25-5
https://www.nxtbook.com/allen/iamm/25-4
https://www.nxtbook.com/allen/iamm/25-3
https://www.nxtbook.com/allen/iamm/instrumentation-measurement-magazine-25-2
https://www.nxtbook.com/allen/iamm/25-1
https://www.nxtbook.com/allen/iamm/24-9
https://www.nxtbook.com/allen/iamm/24-7
https://www.nxtbook.com/allen/iamm/24-8
https://www.nxtbook.com/allen/iamm/24-6
https://www.nxtbook.com/allen/iamm/24-5
https://www.nxtbook.com/allen/iamm/24-4
https://www.nxtbook.com/allen/iamm/24-3
https://www.nxtbook.com/allen/iamm/24-2
https://www.nxtbook.com/allen/iamm/24-1
https://www.nxtbook.com/allen/iamm/23-9
https://www.nxtbook.com/allen/iamm/23-8
https://www.nxtbook.com/allen/iamm/23-6
https://www.nxtbook.com/allen/iamm/23-5
https://www.nxtbook.com/allen/iamm/23-2
https://www.nxtbook.com/allen/iamm/23-3
https://www.nxtbook.com/allen/iamm/23-4
https://www.nxtbookmedia.com