Page 190 - Chalcogenide Glasses for Infrared Optics

166 Cha pte r Se v e n

fibers. Core indices for silicate fibers are < 1.5 while chalcogen-
ide glasses have indices from 2 to 3. Oblique light rays are bent
toward the normal when they enter the core surface. The high-
index glasses bend the oblique rays much closer to the normal,
keeping them in the fiber and away from the core wall.
2. The amount of energy collected was proportional to fiber
diameter.
3. Up to a point, the total energy collected increased with dis-
tance of the fiber from the heated plate as area within the
acceptance angle increased.

In other measurements, the data in Fig. 7.9 show that the C1 As-Se-
Te fiber is much better for measuring temperature from 0 to 100°C

200
190
180
170
160
150
C1
140
Transmitted energy (arbitrary units) 110
130
120

100
90
80
70
60
50
40
30 C2
20
10
0
0 1020304050607080 90 100 110 120 130 140 150
Temperature (°C)
FIGURE 7.9 Temperature measurements with AMI C1 and C2 fi ber.