Abstract
Tilted Fiber Bragg Grating (TFBG) is expected to be used for such sensors as refractometers, twist
sensors, liquid level sensors, chemical sensors and biosensors. We review its fabrication techniques and
its refractive index measurements and developed a simplified technique to fabricate TFBG for
simultaneous measurements of the refractive index and the temperatures of liquids. We used a
combination of a 4ω Nd:YAG laser and a phase mask, which is simpler than a conventional method
using a 2ω cw Ar+ laser and a Lloyd mirror interferometer. We calculated TFBG’s cladding modes by
the multi-layer method and estimated the temperature coefficient of the water’s refractive index to be
about ‒1×10‒4 /K using our fabricated TFBG sensor.
