Studies On The Laser And Other Issues In The PGC Demodulation System Based On Laser Modulation

The fiber-optic hydrophone based on the optical fiber sensing technology is themost ideal underwater acoustic signal detector at present. Fiber-optic hydrophoneshave many advantages such as wide frequency band, high sensitivity, free ofelectromagnetic interference, small volume, light in weight, random shapes to bedesigned, integrating optical transmission and sensor. The phase interferometrichydrophone of the all is investigated most extensively, and its applied ranges haveextended to the engineering and civil fields instead of the pure military use. Forexample, it has become more and more important to monitor the reservoir of thesea.The research of signal demodulation methods is a very important content in thephase interferometric hydrophone field. The detection technique of phase generatedcarrier (PGC) demodulation with laser frequency modulation is capable of highsensitivity, with which all fiber optic hydrophone could be built. Its high sensitivity,large dynamic range and very good linearity have made PGC method become themost suitable technique in the fiber-optic hydrophone detection and mass scalearray.The thesis is supported by the national key project of 863, focused on therealization of a fiber optic sensing system suitable for oil well logging and reservoirmonitoring. The content is focused on the realization of the PGC algorithm usingdigital system, the research of the system and the establishing of the datacommunication. Detailed speaking, it includes the following aspects:1. Based on sufficient research on the recent demodulation techniques offiber-optic hydrophone, the phase generated carrier (PGC) demodulationscheme of interferometric fiber-optic sensor is discussed systemically.2. Through simulations and experiments, we have made a detailed research to thelaser, which is of very importance to the final demodulation results. Given thesystem dynamic range, the band width of the laser has been put forward.3. We have realized the digital demodulation and transmission system usingTMS320C6711 DSP cores and the performance of the system has beendiscussed systemically.4. Considering some possible researches in the future, I have given an improvedPGC demodulation technique.