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Proceedings Paper

Fiber Bragg grating interrogation using a wavelength modulated 1651-nm tunable distributed feedback laser and a fiber ring resonator for wearable biomedical sensors
Author(s): Anirban Roy; Arup Lal Chakraborty; Chandan Kumar Jha
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Paper Abstract

This paper demonstrates the interrogation of a fiber Bragg grating with a flat-topped reflection spectrum centred on 1649.55 nm using only a single mode tunable 1651.93 nm semiconductor laser and a fiber ring resonator. The Bragg shift is accurately measured with the fiber-optic ring resonator that has a free spectral range (FSR) of 0.1008 GHz and a broadband photo-detector. Laser wavelength modulation and harmonic detection are used to transform the gentle edges of the flat-topped FBG spectrum into prominent leading and trailing peaks, either of which can be used to accurately measure spectral shifts of the FBG reflection spectrum with a resolution of 0.9 pm. A Raspberry Pi-based low-cost embedded processor is used to measure the temperature-induced spectral shifts over the range 30˚C – 80˚C. The shift was linear with a temperature sensitivity of 12.8 pm/˚C. This technique does not use an optical spectrum analyzer at any stage of its design or operation. The laser does not need to be pre-characterized either. This technique can be readily extended to all types of tunable diode lasers and is ideally suited for compact field instruments.

Paper Details

Date Published: 23 April 2017
PDF: 4 pages
Proc. SPIE 10323, 25th International Conference on Optical Fiber Sensors, 103234H (23 April 2017); doi: 10.1117/12.2265617
Show Author Affiliations
Anirban Roy, Indian Institute of Technology Gandhinagar (India)
Arup Lal Chakraborty, Indian Institute of Technology Gandhinagar (India)
Chandan Kumar Jha, Indian Institute of Technology Gandhinagar (India)

Published in SPIE Proceedings Vol. 10323:
25th International Conference on Optical Fiber Sensors
Youngjoo Chung; Wei Jin; Byoungho Lee; John Canning; Kentaro Nakamura; Libo Yuan, Editor(s)

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