Author: Wu, Ketian
Title: Fiber laser based acoustic signal detection system
Degree: M.Sc.
Year: 2011
Subject: Hydrophone.
Ultrasonic imaging.
Acoustic surface wave devices.
Optical fiber detectors.
Hong Kong Polytechnic University -- Dissertations
Department: Department of Electronic and Information Engineering
Pages: viii, 47 leaves : ill. (some col.) ; 30 cm.
Language: English
Abstract: The dissertation describes the design and implementation of the demodulator system for an ultrasonic hydrophone. The ultrasonic hydrophone system uses a dual polarization distributed Bragg reflector (DBR) fiber laser as the sensing element. The operation principle is based on the modulation of the birefringence of the fiber laser by high-frequency ultrasound signal. The demodulator recovers the high-frequency ultrasound signal from the frequency modulated (FM) signal obtained from the ultrasonic hydrophone system. Different key circuit modules are built using printed circuit board (PCB). By evaluating the output of the circuit modules, the effectiveness of the design is confirmed. The ultrasonic modulation signal can be recovered by this demodulator. Some further enhancement to the system design is suggested. With this, the ultrasonic hydrophone system and the demodulator are expected to enable the realization of an underwater communication system.
Rights: All rights reserved
Access: restricted access

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