超外差干涉绝对距离测量研究综述

SuperHeterodyne Absolute Distance Interferometry: An Overview

近几年来，基于多波长干涉理论的绝对距离测量技术取得了很大的进展。其中，超外差绝对距离干涉测量可以克服光学元件引起的模耦合误差，这是普通的外差干涉测量所不能避免的。超外差测量还能够实现合成波长相位的实时检测。本文简要介绍了多波长干涉测量（也叫小数重合法）的基本原理，论述和分析了超外差干涉测量的原理，指出了超外差测量的优点。最后，对超外差测量的方案进行了综述，并指出了它们在实际测量中的特点。

: Absolute distance measurement based on multiple wavelengths interferometric theory has been progressing greatly in recent years. It has been demonstrated that superheterodyne absolute distance interferometry (ADI) is effective to overcome some system errors that cannot avoid in common heterodyne interferometers, such as mode coupling caused by optical elements, and can perform real time phase measurement of the synthetic wavelength easily. In this paper, we brief the basic principle of multiple wavelengths ADI that is also called fractional fringe measurement. As the essential part, we relate and analyze the principle of superheterodyne interferometry, and therefrom we point out its some unique advantages. Finally we introduce three superheterodyne ADIs whose synthetic wavelengths are obtained by two fixed lasers, two tunable lasers and one diode laser combined with optical fibers respectively. We also explain their merits in actual measurement.