Study On The High Frequency Response Characteristics And Band Expansion Of Fiber Optic Hydrophone

Although some progress has been made in this high-frequency field,existing interferometric fiber-optic hydrophones still have some common challenges in detecting high-frequency underwater acoustic signals.In recent years,hydrophones have played an increasingly prominent role in marine exploration and underwater early warning detection as a core component of underwater acoustic pressure signal detection.As a new generation of sonar equipment,fiber optic hydrophone systems are rapidly developing in the field of underwater target detection and hydroacoustic communication signal reconnaissance due to their excellent immunity to electromagnetic interference,ease of array formation,resistance to harsh environmental conditions and temperature fluctuations.Due to the difference in the frequency band of hydroacoustic communication signals and the frequency band of underwater target radiation noise signals,it is difficult to apply previous hydrophones to hydroacoustic communication signal reconnaissance above 8 k Hz.This paper aims at the application of underwater target radiation noise and hydroacoustic communication signal reconnaissance and addresses the problems of narrow operating band of fiber optic hydrophone and large fluctuation of acoustic pressure sensitivity on wide band.The main research content and innovation points are as follows:(1)In view of the insufficient analysis of the sensitivity response theory of optical fiber hydrophone in the broadband band,the simulation structure of push-pull hydrophone probe is designed based on static analysis by means of finiteimal analysis.(2)In view of the problem that the numerical modeling of the hydrophone probe response mode is not accurate under the wide band,the overall structure of the push-pull spindle fiber hydrophone probe is constructed by simulation software(COMSOL Multiphysics),and the relationship between the resonance frequency,acoustic sensitivity,anti-acceleration sensitivity,vibration variation and structure size of the fiber hydrophone probe is obtained by mechanics simulation and acoustic analysis.(3)In view of the existing laboratory conditions can not meet the needs of the wideband hydrophone probe sound pressure sensitivity test,through the use of free-field testing for the design of high-frequency interferometry fiber-optic hydrophone probe experimental test,the experimental acoustic pressure sensitivity and acceleration sensitivity measurement data and simulation results were comprehensively compared and mutually verified.