为了使光谱分析仪(Optical Spectrum Analyzer, OSA)能精确测量窄谱宽光信号, 要求光栅转动一圈分辨200万个点。设计了一种基于衍射光栅、直流无刷电机(Brushless Direct Current Motor, BLDCM)和光电编码器的高分辨率光栅定位系统。实现了基于比例--积分--微分(Proportion Integration Differentiation, PID)的高精度闭环调速控制技术, 以驱动BLDCM带动光栅的转动。同时, 高精度光电编码器快速检测并反馈光栅的角位置, 细分电路对编码器的输出信号作进一步细分。将输出信号的分辨率从16000点/圈提升至2048000点/圈, 极大地提升了光栅定位系统的整体分辨率。通过实验测试了光栅扫描速度、波长重复性和波长准确度等性能指标, 验证了光栅定位的精度和分辨率。

In order that the optical spectrum analyzer can accurately measure narrow spectral signals, the grating is required to distinguish 2 million points in one cycle. A high-resolution grating positioning system based on diffraction grating, brushless direct current motor and photoelectric encoder is designed. A high-precision closed-loop speed control technology based on PID is realized which can drive the rotation of the grating. Meanwhile, the high-precision photoelectric encoder can quickly detect and feedback the angle position of the grating, and the subdivision circuit can further subdivide the output signal of the encoder. The resolution of the output signal is improved from 16000 to 2048000 per cycle, which greatly improves the overall resolution of the grating positioning system. The performance indexes such as the scanning speed, wavelength repeatability and wavelength accuracy of the grating are tested by experiments, and the positioning accuracy and resolution of the grating are verified.