Evanescent-field photonic microcells and their applications in sensing

A Micro Bubble Structure Based Fabry–Perot Optical Fiber Strain Sensor with High Sensitivity and Low-Cost Characteristics

“…The micro fiber Fabry–Perot interferometer (FPI) sensor with the advantages of compact structure [1], anti-electromagnetic interference [2], and high sensitivity [3] has taken the leading role in a large number of sensing applications such as strain, high sensitive temperature, high sensitive pressure and so on [4,5,6]. It has been widely used in biomedical, non-destructive health monitoring and other fields; among them, the Fabry–Perot (FP) can be effectively used in the optical fiber tip for a limited space environment.…”

Bragg gratings inscribed in selectively inflated photonic crystal fibers

“…The selectively inflation technique has been reported in [10] and is versatile in fabricating various local SCF structures along a PCF. In the fabrication, the combination effect of the collapsing and expansion of different hole-columns in a PCF eventually forms a region with SCF structure, which have a micro-/nano-sized core supported inside the fiber by several struts and connected at its both sides to the unprocessed PCF regions via low-loss transitions (typically <0.1 dB).…”

“…Among all the possible SCF structures given in [10], the three-hole SCF structure was chosen for grating inscription for the least internal components which would be helpful to minimize the possible scattering and distorting of the grating inscription beam. Figure 2(a) is the cross-sectional image of a three-hole SCF sample produced the by the selective inflation process.…”

“…This grating inscription technique is useful in building various grating-integrated PCF devices, and could also be applied on some other holey fibers for efficient grating inscription. To the PCF, the technique is flexible in making gratings with different properties on the SCF regions with different internal structures, which can be realized by selectively inflating different air-columns in fiber [10]. For example, the gratings inscribed in the SCF regions with highly birefringent core would have two Bragg resonant peaks in spectrum which could be useful in two-parameter sensing.…”

Femtosecond-laser-inscribed sampled fiber Bragg grating with ultrahigh thermal stability

“…This fabrication method eliminates the requirement of a phase mask, and the grating parameters can be easily altered by adjusting fiber motion. SFBGs fabricated by PBP inscription were firstly reported by Marshall et al [12], and the PBP inscription method has demonstrated a remarkable facility for fabricating SFBGs as well as many other types of gratings with customized grating periods, amplitudes, and phases according to specific customer requirements [12][13][14][15]. However, the thermal stabilities of these SFBGs were not investigated in these studies.…”