Spectral-domain tandem interferometry to measure the group dispersion of optical samples

Abstract

A spectral-domain technique based on tandem interferometry is used for measuring the group dispersion of optical samples over a wide wavelength range. The technique utilizes a tandem configuration of a Michelson interferometer and an unbalanced Mach-Zehnder interferometer with a sample inserted into its test arm. First, the theoretical background of the technique is presented and then experiments with individual interferometers and their tandem configuration are specified. In all the experiments the spectral signals are recorded to measure the equalization wavelength as a function of the path length difference, or equivalently the group dispersion. We measure the group refractive index as a function of wavelength for a glass sample of known thickness and for a quartz crystal as well.

Birefringence dispersion in elliptical-core fibers measured over a broad wavelength range by interferometric techniques

“…The group modal birefringences G 01 (λ) and G 11 (λ) for the LP 01 and even LP 11 modes, respectively, can be measured by a method of spectral-domain tandem interferometry 13,16,17 in the setup shown in Fig. 2.…”

“…If the ECF is with G 01 (λ)z >> 0 and the path length difference adjusted in the Michelson interferometer is similarly Δ M >> 0, the spectral signal recoded in the setup by a spectrometer of a Gaussian response function can be represented in the form 13,16,17 …”

Simultaneous Measurement of Group Refractive Index Dispersion and Thickness of Fused Silica Using a Scanning White Light Interferometer

“…The spectral method measures the refractive index by using the periodicity of the fringe. However, it has a disadvantage in that it is difficult to resolve issues where the measurement medium is thick or dispersive, which limits the measurement sample [ 16 ]. Further, the spectral method requires an accurate calibration of the CCD array or spectrometer, which makes it difficult to configure and manage the setup.…”

Tandem interferometry used to measure the group dispersion of optical components

“…10,11 In this paper, a spectral-domain technique employing a tandem configuration of two interferometers is used for a direct measurement of the group dispersion of optical samples over a wide wavelength range. 12 A Michelson interferometer in tandem with an unbalanced Mach-Zehnder interferometer and a sample inserted into its test arm are employed. The spectral signals are recorded for measuring the equalization wavelength as a function of the path length difference adjusted in the Mach-Zehnder interferometer, or equivalently the group dispersion.…”