202 documents found, page 1 of 21

Multipath Interferometer Polished Microsphere for Enhanced Temperature Sensing

Cleaved Silica Microsphere for Temperature Measurement

A sensing structure based on a cleaved silica microsphere is proposed for temperature sensing. The microsphere was cleaved using focused ion beam milling. The asymmetry in the structure introduced by the cut generates not only new cavities but also random interferometric reflections inside the microsphere. These two spectral components can be separated using low-pass and high-pass filters, respectively. The sen...

Temperature independent refractive index measurement using a fiber Bragg gratin...

A fiber Bragg grating was inscribed in an abrupt fiber taper using a femtosecond laser and phase-mask interferometer. The abrupt taper transition allows to excite a broad range of guided modes with different effective refractive indices that are reflected at different wavelengths according to Bragg's law. The multimode-Bragg reflection expands over 30 nm in the telecom-C-band. This corresponds to a mode-field o...

Hollow Microsphere Fabry–Perot Cavity for Sensing Applications

Microfiber Knot With Taper Interferometer for Temperature and Refractive Index ...

A compact sensing structure using two distinct optical devices, a microfiber knot resonator and an abrupt taper-based Mach-Zehnder interferometer (MZI), is presented. The device was fabricated using only CO2 laser processing. The transmission spectrum presents two different components with different sensitivities to different physical and chemical parameters. The sensor was characterized in temperature and refr...

Fabry-Perot cavity based on polymer FBG as refractive index sensor

The use of a polymer fiber as a refractive index sensor is proposed. A fiber Bragg grating is inscribed near the fiber tip and the fiber is cut shorter thus creating a Fabry-Perot cavity. The reflections between the fiber Bragg grating and the fiber end-face create a Fabry-Perot interferometer. The sensor was characterized to refractive index changes at constant temperature and to temperature at constant refrac...

Temperature Compensated Strain Sensor Based on Long Period Gratings and Microsp...

Multimode interference-based fiber sensor in a cavity ring-down system for refr...

This work reports a multimode interference-based fiber sensor in a cavity ring-down system (CRD) for sensing temperature-induced refractive index (RI) changes of water. The sensing head is based in multimodal interference (MMI) and it is placed inside the fiber loop cavity of the CRD system. A modulated laser source was used to send pulses down into the fiber loop cavity and an erbium-doped fiber amplifier (EDF...

Acetone evaporation and water vapor detection using a caterpillar-like microstr...

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 channe...

Mach-Zehnder Based on Large Knot Fiber Resonator for Refractive Index Measurement

A Mach-Zehnder sensor based on a large knot fiber resonator with a diameter of a few millimeters is designed using a single long taper. The long taper of some centimeters is fabricated with a CO2 laser technique. In air, light cannot couple between adjacent sections in the knot, and no signal is observed. However, in liquid, light is less confined and there is coupling between adjacent sections of the knot, res...