研究目的

This paper presents a miscellany of FSS designs developed at the University of Campinas combining the expertise from researches and students of the Laboratory of Photonic Materials and Devices (School of Mechanical Engineering) and the Laboratory of Specialty Fibers and Photonic Materials (“Gleb Wataghin” Institute of Physics), for measuring the properties of liquid samples, including refractive index, concentration, viscosity, and evaporation rate.

研究成果

This paper presented a compilation of optical ?ber specklegram sensors derived from research conducted at the University of Campinas for assessing the properties of liquids, such as refractive index and viscosity. Information regarded to those variables can be still exploited to achieve concentration, humidity, and level measurements. The speckle ?eld spatiotemporal characteristics are very sensitive to the medium enclosing the ?ber, making the performance of the FSS comparable to other OFS. On the other hand, the interrogation setup demanded by FSS is simpler than the typical spectral and interferometric approaches.

研究不足

Despite the high sensitivity, it must be stressed that the specklegram is vulnerable to extraneous effects including ?ber bending, vibration, and temperature ?uctuations. Practical FSS must include auto-referencing and thermal compensation schemes for reestablishing the calibration in long-term operation. Moreover, the sensor dynamic range can be extended by implementing additional specklegram processing steps in order to overcome the saturation of correlation metrics.