Temperature sensors operating near the dispersion turning point of microfiber based two-mode fiber

The dispersion turning point (DTP) of the refractive index (RI) sensitivity based on the tapered twin-mode fiber (TTMF) is explored. Theoretical analysis demonstrates that the RI sensitivity will approach ±∞ at the DTP due to the dispersion factor Г reaching zero. And the position of the DTP is significantly dependent on the diameter of microfiber and the external medium. As a result, the TTMF is immersed into a liquid that possesses a highly thermal coefficient of dn
fluid
/dT=−3.86×10
⁻⁴
/°C to investigate its temperature characteristics. An improved sensitivity of ~ 49.4 nm/
^°
C is achieved, which is a competitive result compared to the state-of- the-art fiber-optic temperature sensors. In addition, such structures have huge application potential for the detection of cardiac biomarkers of disease due to simple detection scheme, quick response time, ease of handling and miniaturation.