In this work, we report a sensing configuration of the fiber taper intrinsic Fabry-Perot interferometer directly inscribed in
single-mode optical fiber tapers with different waist diameters from 14 to 80 μm using a femtosecond laser
micromachining system. By controlling the inscribing depth and intensity of the fs laser pulse, the fringe visibility can
exceed 9.0 dB when the fiber taper waist diameter is around 15 μm, which is sufficient for most sensing applications.
The sensor sensitivity depends on the fiber taper waist diameter, while a smaller diameter corresponds to a large
sensitivity. Different free spectral ranges can be achieved for various cavity lengths. Such a structure can combine the
high sensitivity properties of fiber taper sensors with the high resolution features of Fabry-Perot interferometer sensors.
Meanwhile, this structure can have a number of outstanding advantages, such as its small size, unique geometry, easy
fabrication, low cost and capability for mass production. These fiber taper intrinsic Fabry-Perot interferometer sensors
have high potential in fast detection and high precision measurement while maintaining superior reliability for chemical
and biological sensing.