一种高分辨率光栅光谱仪的光路设计

An Optical Path Design of High-resolution Grating Spectrometer

光谱仪在光纤通信系统中具有非常重要的作用,被用于探测光源光谱辐射特征,测量光源波长、功率和信噪比等关键指标。传统光栅光谱仪通过增加光栅线数和准直光路系统焦距的办法来提高分辨率,却带来成本高、仪器体积大、调试困难等问题。为此,研究提出了基于光栅四次衍射的光谱仪光路设计,通过棱镜和平面镜的多次反射,使光信号经过四次衍射,这可极大提高分辨率并减小光路体积。研究分析了新设计的光路原理,建立了四次衍射中波长与色散率、分辨力之间的关系方程式,并使用Zemax软件进行了仿真模拟。仿真结果与理论计算一致,均表明新光路设计能够满足600 nm～1700 nm波段分光,分辨力C波段大于20 pm,1700 nm时的最高分辨力为13 pm。

The use of spectrometers to detect the spectral radiation characteristics of light sources and measure key indicators such as wavelength, power and signal-to-noise ratio of light sources are very important measurement instruments in optical fiber communication systems. In order to increase the resolution, the conventional grating spectrometer uses the method of increasing the number of grating lines and increasing the aperture of the collimated light path system, which results in the dis- advantages of expensive devices, large size, and the like. In order to solve this problem, a spectrometer optical path design based on holographic grating fourth-order diffraction is proposed. Through multiple reflections of the prism an ror, the optical signal is subjected to four diffractions, which greatly improved the resolution and reduced the ume. The principle of the optical path is analyzed in detail, and the relationship between the wavelength, d the planar miroptical path vol- dispersion rate, and resolution of the fourth-order diffraction is established. The use of Zemax software simulations shows that the optical path design can meet the spectral requirements of the 600 nm-1700 nm band, the C-band resolution is greater than 20 pm, and the maximum resolution of 1700 nm is 13 pm