Fast response in-line gas sensor using C-type fiber and Ge-doped ring defect photonic crystal fiber

Abstract

An in-line chemical gas sensor was proposed and experimentally demonstrated using a new C-type fiber and a Ge-doped ring defect photonic crystal fiber (PCF). The C-type fiber segment served as a compact gas inlet/outlet directly spliced to PCF, which overcame previous limitations in packaging and dynamic responses. C-type fiber was prepared by optimizing drawing process for a silica tube with an open slot. Splicing conditions for SMF/C-type fiber and PCF/C-type fiber were experimentally established to provide an all-fiber sensor unit. To enhance the sensitivity and light coupling efficiency we used a special PCF with Ge-doped ring defect to further enhance the sensitivity and gas flow rate. Sensing capability of the proposed sensor was investigated experimentally by detecting acetylene absorption lines.

In-line microfluidic refractometer based on C-shaped fiber assisted photonic crystal fiber Sagnac interferometer

“…The optical properties of PCFs, such as transmission loss, birefringence, and dispersion, are highly dependent on the RI of the fluids filled in the air hole channels of the PCF. These enabled a lot of novel microfluidic RI sensors, e.g., absorptionbased evanescent-wave sensors [6][7][8][9], FBGs in different types of PCFs [10], LPG in a large-mode-area PCF [11], selective-filling based PCF directional coupler sensor [12]. By filling the analytes into the air holes of a PCF-LPG, Rindorf and Bang achieved a RI sensitivity of 1460 nm∕RIU, which is one order of magnitude higher than conventional LPGs [11].…”

“…There are mainly two approaches to couple light into and out of PCFs after liquid filling [6][7][8][9][10][11][12]. One is to directly splice the PCFs and the standard single-mode fiber (SMF); the other is based on free-space coupling.…”

Chemical and biochemical sensing applications of microstructured optical fiber‐based systems

“…The use of a doped core allowed a higher evanescent interaction as well as lower confinement loss and splicing loss than previous studies on defected core PCFs without doped ring . Finally, although less employed, DC‐PCFs can be used to detect molecules in gas media, such as acetylene .…”

In-line chemical sensor based on C-type fiber and novel photonic crystal fibers with high sensitivity and fast dynamic response

“…The suspended ring core PCF has a central hole core with diameter of d core =62.4 μm and d clad =6.6 μm, respectively. Here the pitch size ᴧ is 1 μm and the ring width wring is 2.8 μm [8]. We numerically analyzed these PCF structures using a full-vectorial finite element method (FEM) [7] and compare its results with that of a conventional PCF.…”

“…In recent years, micro-structured optical fibers, especially photonic crystal fibers (PCFs), have attracted considerable interests for sensing applications due to the fact that micro-holes in PCFs can provide a strong and long interaction between the guided light and gases or liquids filled within the holes of PCFs [7]. In PCF-based sensor, however, the rate of gas diffusion into the micron-sized holes caused various limitations in sensing capability [8]. Several ideas have been proposed to overcome PCF filling issue, which mainly dealt with designing the inlet/outlet components connected to PCFs for efficiently flowing measurands into the holes of fiber.…”