在核数据测量实验中，前端电子学通常利用高带宽放大器将探测器输出的微弱瞬态脉冲信号进行匹配和模拟调理，然后通过模拟电缆送至后端电子学系统进行数字化处理。然而，由于带宽、衰减、干扰等限制因素，在通道数多和传输距离远的情况下，使用长电缆低失真地传输瞬态脉冲信号变得越来越困难。一种解决思路是将后端数字化电子学前置到探测器端，就近对模拟信号进行数字化处理，从而避免了模拟信号长距离传输的问题。然而，前移的数字化系统(特别是高速波形数字化电路)除了给敏感的前端模拟电路带来高频数字干扰外，也增加了读出电子学设计、安装、供电、散热等方面的难度，导致其使用范围受到限制。尤其当前端探测器处于强电场、强磁场、强辐射等极端物理环境中，传统的读出方法将面临巨大挑战。 光纤因其具有高带宽、低损耗、低成本、易于使用等优点而被广泛应用在数字通信中，此时光纤作为数字信号的传输介质而存在。此外，光纤还被用于制作各式各样的传感器，用来传输被调制到光波中的模拟信号，广泛应用在声、光、电、磁等信号的探测中。其中，基于光相位调制技术的模拟信号传输系统具备高带宽、高灵敏度、高动态范围、无源、无电磁辐射、抗干扰能力强等优点。因此，本论文基于光相位调制理论开展瞬态脉冲信号的读出方法研究，充分借鉴光调制、光纤无线电、波形数字化等技术的优点。该方法在探测器前端布置相位调制器，通过电光调制技术，将探测器输出的瞬态脉冲信号调制到光波相位中。经过相位调制的光波通过长距离光纤传输至后端并与参考光发生干涉，干涉信号经高带宽光电探测器转换成电信号，进一步送至PXIe机箱内部的波形数字化插件转换成数字信号，并在FPGA内完成实时解调，从而恢复出原始信号的波形。 本论文的研究工作主要分成两大部分。一是激光调制和光链路研究，本论文采用铌酸锂型相位调制器将待测信号和载波信号调制到光波中，并结合时分复用和空分复用技术搭建了PGC外调制多路复用阵列。二是波形数字化技术和实时数字解调算法研究，本论文实现了系统中关键模块的原型电路，包括调制驱动模块、信号调理模块和数字解调模块，并搭建了基于PXIe平台的读出电子学系统，完成对干涉信号的采集、解调和读出处理。 传输电缆存在的幅度和相位畸变等缺陷，成为制约瞬态脉冲信号大规模、远距离精确测量的瓶颈之一。本论文采用将光纤作为传输介质引入前端电子学进行信号读出的研究思路，可避免模拟电缆所带来的低带宽、高失真等问题，具备灵敏度高、动态范围大、线性度好、抗干扰能力强、前后端光隔离等优势，使其能够应用到相关脉冲信号的读出中，为探测器信号的读出提供新思路。 关键词：光相位调制 PGC调制解调 波形数字化 读出电子学

 In nuclear data measurement experiments, the front-end electronics usually use high-bandwidth amplifiers to match and amplify the weak transient pulse signals, and send them to the back-end electronics through analog cables. However, due to the limitation of bandwidth, attenuation, interference and other factors, it is becoming more and more difficult to transmit transient pulse signals through cables. One way is to place the back-end readout electronics near the detectors. However, the forward-moving digital circuits not only bring high-frequency interference to front-end analog circuits, but also increase the difficulties of design, installation, power supply, and heat dissipation. Especially, when detectors are in an extremely harsh environment such as strong electric field, strong magnetic field and strong radiation, traditional readout methods will face enormous challenges. Optical fibers is widely used in data transmission because of its high bandwidth, low cost, and ease of use. At this time, the optical fiber exists as a medium for digital signal transmission. In addition, optical fibers are also used to fabricate various sensors to transmit analog signals imposed on light waves. It is widely used for the detection of acoustic signals, optical signals, electrical signals and magnetic signals. Among them, the analog signal transmission system based on optical phase modulation technology has the advantages of high bandwidth, high sensitivity, high dynamic range, no electromagnetic radiation, strong anti-interference ability, and so on. Therefore, this thesis proposes an analog signal readout method based on the optical phase modulation. The proposed system use the electro-optic phase modulator to impose the transient pulse signal on the phase of the light wave. The modulated light wave is transmitted to the back-end readout system through the long optical fiber, and then interferes with the reference light. The interference signal is converted into electrical signal by the photodetector, and then sampled by the waveform digitization module. The real-time demodulation algorithm is implemented in the FPGA to restore the waveform of the original signal. The research work of this thesis is mainly divided into two parts, including optical phase modulation method and demodulation algorithm. In this thesis, the lithium niobate phase modulator is used to impose the original signal and carrier signal into light wave. A multiplexing array is also constructed based on time division multiplexing and space division multiplexing. The prototype circuits are implemented, including modulator driver module, signal conditioning module and digital demodulation module. And the readout electronics system based on the PXIe platform is set up to verify the performance of the proposed method. The amplitude and phase distortion of the cable has become one of the bottlenecks restricting the transmission of transient pulse signals. This thesis will use optical fiber to transmit analog signals, which can avoid the problems of high loss and high distortion caused by analog cables. It has the advantages of high sensitivity, large dynamic range, good linearity, strong anti-interference ability, and so on. It can be applied to the readout of transient pulse signals and provides a new method for the readout of detector signals. Key Words: optical phase modulation, PGC modulation and demodulation, waveform digitization, readout electronics