Author: Chen, Shuyang
Title: Breath monitoring based on optical fiber interferometer
Advisors: Yu, Changyuan (EIE)
Degree: M.Sc.
Year: 2019
Subject: Hong Kong Polytechnic University -- Dissertations
Optical fiber detectors
Optical detectors
Biosensors
Department: Faculty of Engineering
Pages: viii, 43 pages : color illustrations
Language: English
Abstract: Healthcare has increasingly drawn attentions from people due to the improvement of living conditions in the modern society. People are willing to invest more money in the health care. Vital signs including respiration rate (RR), heart rate (HR) and blood pressure (BP) are significant parameters for people. Optical fiber sensors with inherent merits including high sensitivity, low cost and electromagnetic interference immunity are promising in the domain of biomedical sensing. In this thesis, two types of vital signs monitors based on optical fiber sensors are demonstrated. A smart monitoring system based on optical fiber interferometer utilizing multi-core fiber (MCF) is proposed in the first section. This seven-core fiber (SCF) interferometer adopting SMF-MMF-SCF-MMF-SMF structure (SMF, single-mode fiber, MMF, multi-core fiber) to excite seven core-modes in the fiber and MMF is used as a splitter and coupler. The length of MMF is a significant parameter which should be optimized by theory and experiment. The monitor can detect the breath signal and three types of body activities can be recognized. A heartbeat monitor based on the optical fiber Mach-Zehnder interferometer (MZI) is demonstrated in the second section. The sensor is based on the simple principle of MZI and can detect heartbeat signals in two positions including lying on the bed and sitting on the bed. The raw data will be processed by wavelet analysis method and the heartbeat signal can be obtained. These fiber optic sensors can be embedded in the mattress and user do not need to wear electronic devices, which realizes a non-invasive and contactless monitoring method. In addition, the monitoring systems can be used at home and in the nursing house to monitor the elder or patients, which can greatly reduce the workload of caregiving.
Rights: All rights reserved
Access: restricted access

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