長(zhǎng)周期光纖光柵在地震檢波器中的應(yīng)用

1、長(zhǎng)周期光纖光柵在地震檢波器中的應(yīng)用摘 要: 地震方法是地震勘探中相當(dāng)重要的一部分，而地震檢波器是地震勘探中最重要的環(huán)節(jié)，其性能直接影響到地震勘探的精度。基于長(zhǎng)周期光纖光柵能透射特定波長(zhǎng)、無(wú)后向反射等優(yōu)點(diǎn)，本文提出了一種新型的長(zhǎng)周期光纖光柵地震檢波器系統(tǒng)。本文以長(zhǎng)周期光纖光柵相位匹配條件為基礎(chǔ)，推導(dǎo)出了長(zhǎng)周期光纖光柵地震檢波器的靈敏度公式。并通過(guò)牛頓第二定律建立了長(zhǎng)周期光纖光柵檢波器的力學(xué)模型，推導(dǎo)出了地震檢波器的傳遞函數(shù)。最后，利用實(shí)例仿真得到了該長(zhǎng)周期光纖光柵地震檢波器系統(tǒng)的幅頻特性曲線圖，并通過(guò)模擬仿真證明了長(zhǎng)周期光纖光柵用于地震檢波器的可行性。而且通過(guò)改變光纖的長(zhǎng)度、質(zhì)量塊的質(zhì)量、阻尼系

2、數(shù)等參量可以得到很好的頻率特性與靈敏度，這為提高該系統(tǒng)的性能指明了方向。關(guān)鍵詞: 長(zhǎng)周期光纖光柵；耦合理論；地震檢波器；傳遞函數(shù)；幅頻特性 Long period fiber grating is used in the geophoneAbstract: Seismic exploration method is an extraordinary important portion of the seismicexploration, while seismic geophone is the first link in the normal working of seismicexplor

3、ation instrument. The performance of the seismic geophone influences the whole seismic exploration technology. Based on the narrow band transmission and free of back reflection features of long period fiber grating, a new type of long period fiber gratings (LPFGs) geophone is presented in this paper

4、. The sensitivity of the long period fiber grating geophone system is deduced with the phase matching of long period fiber grating as preconditions. The mechanic model of the long period fiber grating geophone is established by Newton laws, and the transfer function of the geophone is deduced. The a

5、mplitude-frequency characteristics of the long period fiber grating geophone is achieved and its feasibility is proved by simulating a simple example. The proper frequency feature and sensitivity can be achieved by changed the length of optical fiber, the mass of mass block and the damping factor, w

6、hich points a new way for improving the performance of this system.Key words： Long period fiber grating; Coupling theory; Geophone；Geophone transfer function; Amplitude-frequency characteristic 目 錄第一章 緒論11.1 地震勘探技術(shù)及應(yīng)用11.2 光纖地震檢波器的研制背景11.3 本論文的研究目的3第二章 地震檢波器42.1 地震檢波器的發(fā)展42.2 地震檢波器的類型、原理及特性42.2.1 常規(guī)地震

7、檢波器42.2.2 數(shù)字地震檢波器82.2.3 超級(jí)地震檢波器（高精度檢波器）92.2.4 光纖式檢波器102.2.5 壓阻式地震檢波器102.3 地震檢波器的技術(shù)指標(biāo)11第三章 光纖光柵133.1 光纖光柵的概念133.2 光纖光柵的發(fā)展133.3 光纖光柵的分類153.3.1 根據(jù)周期分類153.3.2 根據(jù)波導(dǎo)結(jié)構(gòu)分類162.3.3 根據(jù)形成機(jī)理分類193.3.4 根據(jù)折射率調(diào)制分類193.3.5 根據(jù)材料分類20第四章 長(zhǎng)周期光纖光柵214.1 長(zhǎng)周期光纖光柵研究概況214.2 長(zhǎng)周期光纖光柵的理論224.2.1 耦合模理論234.2.2 長(zhǎng)周期光纖光柵耦合模的理論分析244.3 長(zhǎng)周期光纖光柵軸向應(yīng)變特性理論分析254.3.1 長(zhǎng)周期光纖光柵的溫度特性理論分析264.3.2 長(zhǎng)周期光纖光柵的軸向應(yīng)變特性的理論分析274.4 長(zhǎng)周期光纖光柵在實(shí)際中的應(yīng)用30第五章 基于長(zhǎng)周期光纖光柵的地震