Bragg grating in a single-mode photosensitive polymer optical fiber (POF) with benzil dimethyl ketal
(BDK)-doped in core has been inscribed through the Sagnac ring interference method. The Bragg
wavelength of grating is about 1570nm. The stress and strain response of fiber Bragg grating (FBG)
has been studied respectively. By fitting the experimental result, the strain sensitivity of FBG in POF
has been found to be almost same to that of conventional silica fiber Bragg gratings. However, the
stress sensitivity of FBG in POF is measured to be 421pm/MPa, which is 28 times higher than FBG in
silica fiber. And such high stress sensitivity makes Bragg grating in a single-mode BDK-doped POF
appear to be very attractive for constructing stress sensor with high resolution.