Acetone evaporation and water vapor detection using a caterpillar‐like microstructured fiber

Abstract

power divider incorporating k/4 transformers is properly designed to feed the array elements. The elements of the array are spaced at a distance of 0.8k 0 from each other in both x-and y-directions.ABSTRACT: A new microstructured optical fiber is presented as a sensor of acetone evaporation. Sensing is performed by observing the time response of the reflected signal at 1550 nm when the device is dipped in acetone or a 50% acetone-50% water mixture. The sensor consists on a caterpillar-like microstructured fiber spliced to a single-mode fiber, where the spliced end of the sensor has a transversal microfluidic channel etched using focused ion beam. Upon heating, different behaviors are visible between the dipping and the evaporation of acetone. The sensor is able to track the evaporation of acetone and to distinguish between pure acetone and a 50% acetone-50% water mixture. The sensor is also able to detect when the acetone in a mixture with water is fully evaporated. The detection of water vapor with no particular orientation of the sensor is achieved due to the presence of the microfluidic channels.ABSTRACT: This article presents a thorough investigation of the use of shorting posts to widen the bandwidth and coupling coefficient range of a patch quadrature coupler. The lumped equivalent circuit is used to analyze the characteristics of two proposed shorting posts loaded patch configurations. It is shown that by loading shorting post on the center of a patch, the bandwidth of coupler with loose coupling can be significantly improved. The patch configuration with four shoring posts is also proposed to provide a loose coupling coefficient up to 15 dB, which cannot be achieved using the conventional configuration. For demonstration purposes, two quadrature couplers were designed to exhibit 10 and 15 dB coupling coefficients with bandwidths of 29% and 19.2%, respectively. V C 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:683-688, 2016; View this article online at wileyonlinelibrary.com.

A review of focused ion beam applications in optical fibers

“…It has also been effectively used to cleave and polish the fiber endfacet [131][132][133][134][135][136][137]. In addition, FIB machining has been employed for fabricating lab-aroundfiber and lab-in-fiber devices such as microgratings [138][139][140][141][142][143][144][145][146][147][148][149][150], microcavities [151][152][153][154][155][156][157][158][159][160], as well as access holes and channels [161][162][163][164][165][166][167][168][169]. It is worth mentioning that the beam shaping structures fabricated on the fiber tip predominate in FIB applications in optical fibers (figure 7).…”

“…Alternatively, the sample can be inserted through an access channel created in the fiber cladding, leaving the fiber endfacets free for optical access. FIB machining, which enables precise control of the depth and shape of an opening, has been effectively used to mill channels for lateral access to the longitudinal fiber air-holes without interfering with the fiber endfacet [161][162][163][164][165][166][167][168][169].…”

“…In this case, the PCF holes connected to the channels would be filled if the spliced fiber was immersed into a fluid. Furthermore, Gomes et al reported a sensor composed of a caterpillar-like MOF spliced to a single-mode optical fiber, where the spliced endfacet contains FIB-milled transversal microfluidic channels [165].…”

Micro and Nanostructured Materials for the Development of Optical Fibre Sensors

“…There are also some drawbacks such the influence of ambient pressure: to overcome it, designs are under study and they are currently in a development stage [ 52 ]. Other fabrication approaches include the cladding functionalization to attach sensing coatings more easily [ 53 ], while ion beam technique is also used to create microfluid channels on the fibre [ 54 ].…”

Optical Fiber Sensor for Monitoring the Evaporation of Ethanol–Water Mixtures

“…A different approach was followed by Preter et al, where the evaporation of a droplet located at the fiber tip [ 20 ] or in an in-fiber micro-cell [ 21 ] was monitored by means of optical power variations. Tip sensors based on microstructured optical fibers have also been employed to monitor the evaporation of fluids [ 22 , 23 ]. Many other sensing devices have been proposed to detect and monitor VOCs, and thorough reviews can be found in [ 11 , 14 , 15 ].…”