为了解决光纤多普勒测振仪远距离非接触测量物体振动时，信号偏弱、过零点波形凌乱、难于解调的问题，本文提出了一种新型光纤准直系统。本系统主要采用在小型C-lens光纤准直器后端增加整形系统并借助ZEMAX软件对高斯光束进行准直并优化，通过对光纤准直系统成品进行耦合测试实验，使用C-lens准直器与光纤准直系统进行信号耦合效率的测试对比。实验结果表明：改进后的准直系统能够满足2 m的工作距离，空间返回光耦合效率最大能达到6.3%，极大地提升了多普勒信号的对比度，提高了远距离光纤多普勒测振仪对振动的测量精度。

In order to solve the problem of weak signal, messy waveform at zero-point and difficult demodulation, when the optical Doppler vibrometer in the long-distance non-contact measurement, in this paper, a new type of optical fiber collimation system is proposed. The system mainly uses an augmented beam shaping system at the end of a small C-lens optical fiber collimator and the Gaussian beam is collimated and optimized by ZEMAX software. Through the coupling test of finished product of optical fiber collimation system, and compared with the signal coupling efficiency of C-lens collimator. The experimental results show that the improved collimation system can meet the working distance of 2 meters, and the coupling efficiency of space return optical up to 6.3%, which greatly enhances the Doppler signal contrast and improves the long-distance optical fiber Doppler vibration measurement accuracy.