Iranian Nanotechnology Society International Journal of Nanoscience and Nanotechnology 1735-7004 18 2 2022 05 01 Performance Evaluations of Ammonia ‎Sensors Using Cladding Modified Single-‎Mode Optical Fiber Coated with ‎Polyaniline Nanofibers 135 141 252429 EN H. A. Mohammed ‎Electronic and Communication Engineering Department, College of Engineering, University ‎of Baghdad, Baghdad, Iraq Wireless and Photonics Network Research Centre, Faculty of Engineering, Universiti Putra ‎Malaysia, 43400 UPM, Serdang, Selangor, Malaysia 0000-0002-6001-2500 A. Almamori ‎Electronic and Communication Engineering Department, College of Engineering, University ‎of Baghdad, Baghdad, Iraq S. Girie Wireless and Photonics Network Research Centre, Faculty of Engineering, Universiti Putra ‎Malaysia, 43400 UPM, Serdang, Selangor, Malaysia Department of Computer Engineering, Federal Polytechnic Mubi, Adamawa State, Nigeria M. H. Abu Bakar Wireless and Photonics Network Research Centre, Faculty of Engineering, Universiti Putra ‎Malaysia, 43400 UPM, Serdang, Selangor, Malaysia S. B. A. Anas Wireless and Photonics Network Research Centre, Faculty of Engineering, Universiti Putra ‎Malaysia, 43400 UPM, Serdang, Selangor, Malaysia M. A. Mahdi Wireless and Photonics Network Research Centre, Faculty of Engineering, Universiti Putra ‎Malaysia, 43400 UPM, Serdang, Selangor, Malaysia M. H. Yaacob Wireless and Photonics Network Research Centre, Faculty of Engineering, Universiti Putra ‎Malaysia, 43400 UPM, Serdang, Selangor, Malaysia Journal Article 2021 12 11 <em>   In this paper, we developed a cladding modified optical fiber to detect low concentrations of ammonia (NH₃). The Modification is coating with polyaniline (PANI) nanofibers. By using single mode optical fiber (SMF), two sensors are fabricated. The first one is etched with the chemical agent which is hydrofluoric acid (HF), and the other is tapered with a glass processing workstation so that the waist diameters of 15 µm for both modified sensors. Modified fibers are spray coated. The modification done on SMFs considerably enhances the interaction between them. The proposed modification is considerably enhancing how the evanescent field and the (PANI) sensing layer interact with each other. The modified SMF sensors are subjected to NH₃ with different concentrations within the visible wavelength range. The modified SMF and the nanostructured PANI films pattern results in a highly sensitive ammonia sensor at room temperature. The tapered SMF coated with PANI works better compared with the etched SMF. The results show that the response equals 89s, the recovery times equal 433s, and the sensitivity equals 139.1%. The modified fiber sensors have a limit of detection (LOD) of 0.0034% (34 ppm).</em> https://www.ijnnonline.net/article_252429_c2f615e5e217ab9e5f6f0c3f83438e9a.pdf