To extract only distortion by eliminating effect of a temperature change T generated in an FBG sensor.
The sensor 1 is structured of a first fixing body 10 and a second fixing body 20 respectively having a coefficient of thermal expansion same as that of an object 50 to be measured, having sides 11, 21 facing with each other on a surface of the object 50 to be measured, and fixing at a predetermined interval L1, a pair of FBG sensors 2, 3 bridged between both of the fixing bodies 10, 20 and fixed on both of the fixing bodies 10, 20. A first extending part 12 is provided on an opposite side 11 of the first fixing body 10, wherein the first extending part 12 extends to the second fixing body 20 side, and includes an opposite edge 13 partially formed so as to face to the opposite side 11 through a clearance S. A second extending part 22 is provided on an opposite side 21 of the second fixing body 20, wherein the second extending part 22 extends to the first fix body 10 side, and includes an opposite edge 23 partially formed so as to face to the opposite edge 13 of the first extending part 12 at a predetermined interval L2 in the clearance S. The one FBG sensor 2 is fixed on a line connecting the opposite edges 13, 23 of the extending parts 12, 22 of both of the fixing bodies 10, 20. The other FBG sensor 3 is fixed on a line connecting the opposite sides 11, 22 of except for the extending parts 12, 22 of both of the fixing bodies 10, 20.
NAKANO TATSUJI
MIURA SATORU
NAKAMURA KENICHI
ANRITSU CORP
Reijiro Ichihigashi