Study On The Hydroacoustic Sensing Characteristics Of Silicon Dioxide Optical Waveguide Resonator Cavity

China has been a major maritime country since ancient times,with superior Marine resources and a coastline as long as 32,000 km,which has an urgent need for the exploration of Marine environment and underwater targets.Therefore,the development of high-quality hydroacoustic sensor equipment is of great significance.Compared with the traditional diaphragm acoustic sensors are prone to the limitation of their own resonance frequency,resulting in low sensitivity of underwater acoustic detection.The optical waveguide resonator（Optical Waveguide Resonator,OWR）structure has strong local enhancement effect and frequency selection characteristics,which provides a feasible way to improve the sensitivity of underwater acoustic sensor and broaden the working frequency range.In this paper,using Ge doped silicon dioxide as the core material of optical waveguide,the photoacoustic sensing principle,structural design,fabrication process,and underwater acoustic sensing effect of silicon dioxide optical waveguide resonators have been deeply studied.The main work of this paper is as follows:First of all,this paper combs the research process of optical waveguide resonator and its research process in acoustic sensing,the basic structure and optical transmission characteristics of optical waveguide resonators are introduced,and finally the acoustic sensing mechanism of optical waveguide ring resonator structures is analyzed;Secondly,the optical waveguide resonator structure is simulated and numerically simulated to design the appropriate cavity length,coupling spacing and microgroove size;Then,the preparation process of silicon dioxide optical waveguide resonator acoustic sensor is introduced in detail,and the performance test of the prepared silicon dioxide optical waveguide resonator device is carried out;Finally,a test system of underwater acoustic sensor based on silicon dioxide waveguide cavity is built.The test system can realize the signal modulation synchronous demodulation function and the resonant point frequency locking function.The frequency response characteristics of the silicon dioxide optical waveguide resonator underwater acoustic sensor were obtained by testing low-frequency underwater acoustic signals with the same amplitude and different frequencies;by testing low frequency water signals with different amplitudes at the same frequency in a silicon dioxide optical waveguide resonator,the sensitivity of the silicon dioxide optical waveguide resonator underwater acoustic sensor is obtained;The signal to noise ratio and the minimum detectable sound pressure of the silicon dioxide optical waveguide resonator underwater acoustic sensor were measured,and the stability test was conducted.The results show that the Q value of the silicon dioxide optical waveguide resonator is1.69×10⁶,the highest sensitivity from 10 Hz to 2 k Hz is-142.6 d B@160Hz,the frequency response is flat at 40 Hz to 1600 Hz,with no more than±3 d B,and the minimum detectable sound pressure at 1 k Hz is 0.05 Pa/Hz^1/2.The new structural underwater acoustic sensor piece proposed in this paper has a good application prospect in the field of high sensitivity and wide band underwater acoustic sensing.