Group index dispersion of holey fibres measured by a white-light spectral interferometric technique

Abstract

We present a new white-light interferometric technique to measure the group index of holey fibres over a wide wavelength range. The technique utilizes an unbalanced Mach-Zehnder interferometer with a fibre under test of known length placed in one of the interferometer arms and the other arm with adjustable path length. In a first step, the differential group index of the fibre is measured over a wide wavelength range. In a second step, the fibre is replaced by the reference sample of known thickness and group dispersion to determine precisely the group index of the fibre at one specific wavelength. The group index as a function of wavelength is measured for two different holey fibres, one made of pure silica glass and the other made of SK222 glass. For both fibres, the wavelength dependence of the group index of the outer cladding and modes supported by the fibre is measured.

Polarization Sensitive Optical Coherence Tomography with Spectroscopic Analysis

“…The OCT is based on the interference of the light beams, which have a short temporal coherence (white light interferometry (WLI) or low-coherence interferom-etry (LCI)). Thereby the light backscattered from the particular scattering points inside the investigated object can be selectively detected, which is needed for tomography imaging [1,2,[10][11][12][13][14][15][16]. There are several types of OCT systems [7,11].…”

Broad spectral range measurement of chromatic dispersion of polarization modes in holey fibers by interferometric techniques

“…First, a spectral interferometric technique employing an unbalanced Mach-Zehnder interferometer with a BHF in the test arm 16,21,26 is used for measuring the wavelength dependence of the differential group effective index of the one of the polarization modes supported by the fiber. We apply a five-term power series fit to the measured data and by its differentiation we obtain the chromatic dispersion.…”

Broadband near-infrared fibers dispersion measurement using white-light spectral interferometry

“…Previously, the spectral method with a broadband halogen lamp serving as a light source has been used to measure the dispersion of regular and photonic fibers in a wide range of wavelengths of the visible light (500-900 nm [5][6][7]). It has been also applied to measurements in the near-infrared (1450-1650 nm [8][9][10]) with bright albeit spectrally narrow sources (LEDs, SLEDs and lasers) and with supercontinuum source in range 1100-1700 nm [11].…”

“…In order to retrieve the fiber dispersion from the data recorded with the spectral interference method one of the two commonly used approaches can be selected: (1) the Fourier transform [7] and (2) the analysis of the equalization wavelength (stationaryphase point) position as a function of the length of reference arm [5]. Both require a good spectral resolution.…”