We demonstrate experimentally the two-terminal magnetic sensors exhibiting an extraordinary magneto-resistance effect by using an InGaAs quantum well channel with a metal-shunting structure. A high magneto-resistance of 17.3% and a sensitivity of 488.1 Ω/T have been obtained at 1 T and room temperature with our geometrical design. The two-contact configuration and the high-mobility electron transistor-compatible epitaxy structure make the devices promising for high-sensitivity magnetic sensing integration and applications.

In this paper, we design and demonstrate an all-fiber-sensitive refractive index (RI) sensor based on the Mach–Zehnder interferometer (MZI). It is constructed by splicing two no-core fibers (NCFs) and a photonic crystal fiber (PCF) between two single-mode fibers (SMFs) to obtain an SMF–NCF–PCF–NCF–SMF composite structure (SNPNS). A study of the effect of varying PCF lengths on the RI reveals that the shorter the length, the higher the sensitivity. The maximum RI sensitivity of 176.9 nm/RIU is attained within the RI range of 1.3365–1.3767 when the PCF length in the SNPNS structure is 3 cm. Meanwhile, the sensor exhibits a high stability in water, with an RSD of only 0.0019% for the interference trough over a duration of two hours. This proposed sensing structure offers the advantages of a large extinction ratio, small size, low temperature sensitivity, and simple fabrication, exhibiting a great potential in RI measurements.

In this paper, a novel refractive index (RI) sensor based on the soliton self-frequency shift (SSFS) in tellurite photonic crystal fiber (TPCF) is proposed. RI sensing in the mid-infrared region is achieved by detecting the wavelength shift of the soliton. By exploiting the high RI property of the tellurite fiber, it is possible to measure surrogate liquids with higher RIs compared to conventional silica fibers. The sensitivity of the proposed sensor can reach up to 3657.5 nm/RIU when a fiber laser with a pulse width of 100 fs and pump wavelength (λP) of 2600 nm is used as the light source and a 1 m-long TPCF is utilized as the nonlinear medium. To the best of our knowledge, this is the first time that high RI sensing in the mid infrared region has been achieved by exploiting the SSFS effect in non-silica fibers such as TPCF.