RESUMO
An optical fiber sensor for simultaneous measurement of humidity and temperature is proposed and investigated. The sensor is composed of a pokal taper and a peanut taper spliced at both ends of a single-mode fiber, respectively. In the experiment, the variations of the dip wavelength are used to measure the parameter sensing characteristics. The sensing area is coated with a concentration of 1 mg/ml graphene dispersion by using the optical driven deposition method. Experimental results show that the sensor has a good linear relationship with temperature and humidity. When the humidity measurement range is 30%RHâ¼70%RH, the sensitivities are 0.059 nm/%RH and 0.133 nm/%RH, respectively. When the temperature measurement range is 0∘Câ¼40∘C, the sensitivities are 0.254 nm/°C and 0.269 nm/°C, respectively. This sensor has the advantages of small size, low cost, and high response.
RESUMO
An in-line optical fiber sensor is proposed and demonstrated for simultaneous measurement of temperature and refractive index (RI). This sensor can be obtained by splicing two pokal-taper structures and a segment of thin-core fiber (TCF). The middle segment of the TCF works as the sensing region, and the two pokal-taper structures work as an exciter and a coupler. The transmission spectra formed by different lengths of TCF are analyzed theoretically, and then the appropriate length is selected during the experiment. The purpose of simultaneous measurement of temperature and RI can be achieved due to the different parameter responses of the two dips used in the experiment. The sensitivities of the two dips are 0.082 and 0.086 nm/°C in the temperature range of 20°C to -20°C. The sensitivities of the two dips are -43 and -30.83 nm/RIU in the RI range of 1.335-1.37. The proposed sensor has many advantages and wide application prospects.