High-sensitivity refractive index sensor based on large-angle tilted fiber grating with carbon nanotube deposition

Abdulyezir A. Badmos, Qizhen Sun, Zhijun Yan, Raz N. Arif, Junxi Zhang, Alex Rozhin, Lin Zhang

Research output: Chapter in Book/Published conference outputConference publication


This paper presents a highly sensitive ambient refractive index (RI) sensor based on 81° tilted fiber grating (81°-TFG) structure UV-inscribed in standard telecom fiber (62.5μm cladding radius) with carbon nanotube (CNT) overlay deposition. The sensing mechanism is based on the ability of CNT to induce change in transmitted optical power and the high sensitivity of 81°-TFG to ambient refractive index. The thin CNT film with high refractive index enhances the cladding modes of the TFG, resulting in the significant interaction between the propagating light and the surrounding medium. Consequently, the surrounding RI change will induce not only the resonant wavelength shift but also the power intensity change of the attenuation band in the transmission spectrum. Result shows that the change in transmitted optical power produces a corresponding linear reduction in intensity with increment in RI values. The sample shows high sensitivities of ∼207.38nm/RIU, ∼241.79nm/RIU at RI range 1.344-1.374 and ∼113.09nm/RIU, ∼144.40nm/RIU at RI range 1.374-1.392 (for X-pol and Y-pol respectively). It also shows power intensity sensitivity of ∼ 65.728dBm/RIU and ∼ 45.898 (for X-pol and Y-pol respectively). The low thermal sensitivity property of the 81°-TFG offers reduction in thermal cross-sensitivity and enhances specificity of the sensor.

Original languageEnglish
Title of host publicationOptical Sensing and Detection IV
EditorsFrancis Berghmans, Anna G. Mignani
Number of pages9
ISBN (Electronic)978-1-5106-0144-4
Publication statusPublished - 29 Apr 2016
EventOptical Sensing and Detection IV - Brussels, Belgium
Duration: 3 Apr 20167 Apr 2016

Publication series

NameSPIE Proceedings
ISSN (Print)0277-786X
ISSN (Electronic)2410-9045


ConferenceOptical Sensing and Detection IV

Bibliographical note

Abdulyezir A. Badmos ; Qizhen Sun ; Zhijun Yan ; Raz N. Arif ; Junxi Zhang ; Alex Rozhin and Lin Zhang, "High-sensitivity refractive index sensor based on large-angle tilted fiber grating with carbon nanotube deposition", Proc. SPIE 9899, Optical Sensing and Detection IV, 989916 (April 29, 2016).

Copyright 2016. Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.

DOI: http://dx.doi.org/10.1117/12.2227703


  • ambient medium
  • attenuation band
  • carbon nanotubes
  • cross-sensitivity
  • optical power
  • refractive index
  • resonant wavelength
  • sensitivity
  • Tilted Fibre grating
  • wavelength shift


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