提出了一种以集成光学声光可调谐滤波器作为分光元件的新型光谱仪,并详细介绍了这种光谱仪的具体特性。通过对这种光谱仪的特征方程、点扩展函数以及色散本领的详细分析,指出该光谱仪的分辨本领与器件的声光作用长度成正比,也与它的级联级数的平方根成正比。因此增加器件的声光作用长度比增加它的级联级数能更有效地提高光谱分辨率。另外还指出,准共线声光耦合是抑制侧瓣、提高分辨本领的有效途径。测试表明,当声光相互作用长度L=25 mm,声波导和光波导的夹角θ=0.42°时,在中心频率174 MHz附近可获得带宽1.44 nm,一级侧瓣-13.2 dB,模式转换效率大于99%的结果。

An integrated optical acoustooptic tunable filter (AOTF)-based new type spectrometer is brought forward, and its characteristics are introduced in detail. Through analysis of the transmission functions, point spread function and dispersion power of the spectrometer detailedly, it is pointed out that the spectral resolution is proportional to acoustooptic interaction length L, and the square root of the number of stages. So the resolution can be enhanced more effectively by increasing acoustooptic interaction length L than increasing the number of stages. In addition, it is proposed that quasi-collinear acoustooptic coupling is a effective way to suppress sidelopes and improve the resolution of AOTF spectrometer. The testing the quasi-collinear device shows that as the acoustooptical coupling length is 25 mm and the angle between acoustical and optical waveguid is 0.42°, it is obtained that the measured FWHM is 1.44 nm when the acoustic frequency is about 174 MHz,the measured sidelobes level is -13.2 dB and the mode-conversion efficiency of 99%.