Thermo-optic coefficient measurement of liquids based on simultaneous temperature and refractive index sensing capability of a two-mode fiber interferometric probe

Abstract

A fiber-optic interferometric probe based on a two-mode fiber (TMF) is proposed and demonstrated for measuring the thermo-optic coefficients (TOCs) of liquid samples. The proposed probe can be simply fabricated by fusion-splicing a short piece of TMF to a lead single mode fiber (SMF) with small lateral offset, which makes interference between LP(01) and LP(02) modes. The sensing responses of the probe to temperature and surrounding refractive index (SRI) have been experimentally investigated to show the capability of simultaneous measurements; the phase change of the reflection spectrum was related to temperature variation and the intensity change was to SRI variation. The data analysis is made not only in the spectral domain but in the Fourier domain also to effectively quantify the measurements. The TOCs of several liquid samples including water, ethanol, and acetone have been obtained with the proposed method.

Cladless few mode fiber grating sensor for simultaneous refractive index and temperature measurement

“…It should be noted that in the experimental results each data point is the mean of five readings with error bar representing the deviation from mean value. By considering the similar methods for the measurement of the accuracy, sensitivity, and the repeatability as in [26,27], it has been investigated that the proposed sensor is more accurate (0.5% error) due to the inclusion of cross-sensitivity factor, and high sensitive (specifically for higher order mode for RI measurement as shown in Fig. 6) and exhibits the high repeatability with deviations of ±8 × 10 −4 and ±1 • C in the measurement of RI and temperature respectively.…”

A Compact All-Silicon Temperature Insensitive Filter for WDM and Bio-Sensing Applications

“…Bulk refractive index of the cladding is increased from 1.31 to 1.35 of a fluid cladding [9] . DI water TO coefficient is taken from [10]. The simulations were performed for the differential signal: both arms exposed to the same cladding change, as well as the TE arm and TM arm separately, and this was simulated for two different temperatures of 20 °C and 50 °C respectively.…”

A digitally generated ultrafine optical frequency comb for spectral measurements with 0.01-pm resolution and 0.7-µs response time

“…The other reason is that the TOC itself is also temperature dependent (although only weakly). 35,36 Because they were limited by spectral resolution, many previous studies used a large temperature range (e.g., DT ,20 6 C in Ref. 34), and the TOC obtained in such studies is in fact the value averaged over that temperature range.…”