Temperature characteristics of the birefringence properties of filled side-hole fibers

Abstract

The temperature characteristics of the birefringence of side-hole fibers filled with liquids or metal are investigated, aiming at providing a basis for on/off temperature sensing. Short pieces of fiber are filled and the change in birefringence is registered using measurements in reflective mode of the transmitted power through a linear polarizer at 1550 nm. The rapid change in the birefringence behavior of the fiber at the temperature of the phase transition of the filler substance is shown, and from the measurement data the phase transition temperatures can be determined as well as an estimation of the birefringence change with temperature. The experimental results are supported by numerical simulations.

Influence of filler metal on birefringent optical properties of photonic crystal fiber with integrated electrodes

“…Indium is expected to induce a very large thermal stress since the thermal expansion coefficient of this metal is at least one order of magnitude larger than that of the fiber material. The fact that the optical and mechanical properties of the PCF can be custom-designed over a wide range is a potential advantage of these waveguides relative to conventional fibers with internal electrodes [10].…”

Highly sensitive temperature sensor using a Sagnac loop interferometer based on a side-hole photonic crystal fiber filled with metal

“…[1][2][3][4][5][6][7], with temperature sensors being the most studied and applied in recent years in the field of monitoring processes. Fiber gratings-fiber Bragg gratings (FBGs) [8,9] and long-period fiber gratings (LPGs) [10]-conventional high-birefringence (HiBi) optical fibers [11][12][13][14], waist-enlarged fusion bitaper [15], liquid-sealed tapered fibers [16], filled side-hole fibers [17][18][19][20], and filled photonic crystal fibers (PCFs) [21][22][23][24] have especially attracted great interest in temperature-sensing applications. Temperature sensors based on standard fibers have several drawbacks, mainly due to their low temperature sensitivity and a high sensitivity to bending and polarization [19].…”

“…However, the SLI sensor is usually quite long (≈72 cm) due to the limited birefringence of conventional HiBi fibers, which is not convenient for practical use. Side-hole conventional fibers offer a structure that can be modified to create a change in the birefringence of the fiber by varying the mechanical stress in the fiber through properties of the filling material, such as metals or liquids that undergo a thermodynamic phase transition [17][18][19][20]25]. For example, a SLI temperature sensor based on 20-cm-long side-hole conventional fiber filled with indium (In) [18] has been presented by Kim et al, achieving a high sensitivity of −6.3 nm∕°C in the temperature range 27°C-115°C.…”

“…Note that the maximum operating temperature of this type of sensor is limited by the melting point of filler metals. When the metal is completely melted, only a minor temperature dependence remains, since the radial stress from the metal in the holes is relaxed [20].…”

Coupled thermal-optic effects and electrical modulation mechanism of birefringence crystal with Gaussian laser incidence

“…Wu et al [16] studied the influences of the temperature field on birefringence and beat length in a high birefringence photonic crystal fiber and pointed out that PCF is more sensitive to temperature. Ja-son et al [17] studied the influences of the phase change temperature on birefringence in liquid-and metal-filled side-hole fibers, thus providing the basis for the on/off temperature sensing function. Zhao et al [18] studied the birefringence effect in a polarization maintaining photonic crystal fiber and pointed out that its ultra-low temperature dependence feature is helpful for the application in the temperature-insenstive fiber interferometer, fiber sensor, and fiber gyroscope.…”