基于虚像相位阵列(virtual image phased array,VIPA)的布里渊光谱技术是一种高分辨率光谱探测技术。它具有实时监测、高灵敏度等优点。目前该技术主要通过VIPA的自由光谱范围(free spectral range,FSR)与像素映射关系获取频率信息。然而,入射光角度变化会造成FSR波动。传统的测量手段均基于FSR不变的前提下进行,不能对测量过程中入射角度改变导致的FSR变化进行实时标定,从而造成测量结果出现误差。本文针对这一问题,通过分析布里渊散射特点和VIPA干涉原理,提出基于单模光纤布里渊频移的FSR实时校准方法以及相应的像素与频率映射关系计算方法。该方法利用单模光纤的布里渊斯托克斯与反斯托克斯光频移作为参考,减小由入射光角度变化引起的FSR波动造成的频率测量误差。实验利用该方法实现了532 nm波长下不同折射率环境中的微纳光纤布里渊频移的快速测量。

The Brillouin spectroscopy technique based on virtual image phased array (VIPA) is a high-resolution spectral detection technique.It offers advantages such as real-time monitoring and high sensitivity.Currently,this technique primarily relies on the mapping relationship between the free spectral range (FSR) of VIPA and the pixel to obtain frequency information.However,variations in the incident light angle can cause fluctuations in the FSR.Traditional measurement methods are based on the assumption of constant FSR and do not provide real-time calibration for FSR changes caused by variations in the incident angle,resulting in measurement errors.In this paper,we address this issue by analyzing the characteristics of Brillouin scattering and the interference principle of VIPA.We propose a real-time calibration method for FSR based on the Brillouin frequency shift of a single-mode fiber and a corresponding calculation method for pixel-to-frequency mapping.This method utilizes the Brillouin Stokes and anti-Stokes frequency shifts of a single-mode fiber as references to reduce frequency measurement errors caused by FSR fluctuations due to changes in the incident light angle.Experimental results demonstrate the rapid measurement of micro/nano fiber Brillouin frequency shift in different refractive index environments at a wavelength of 532 nm using this method.

O433.1

国家自然科学基金(62075086) 资助项目