Paper deals with measurement of polarization properties of fibers along incidence of different external effects as temperature, torsion and magnetic field. Study of polarization is important from the polarization dispersion point of view for communication systems and also in the area of interferometric and polarization sensors or general interferometric measurements. Analysis of individual effects is solved theoretically and practically in the series of works. Our contribution solves a relatively short part of fiber, where additionally fluctuation of power between both polarization modes could affect.

In precision length measurements the accurate and traceable value of the linear thermal expansion coefficient (LTEC) is needed. A device for interferometric determination of the LTEC of gauge blocks has been constructed. Minimum temperature gradients in a gauge block with 500 mm maximum length and relatively fast operation were the objectives of this project. Based on uncertainty analysis LTEC can be measured with a standard uncertainty of 0,02·10^-6 1/K for 100 mm gauge blocks.

We have investigated the intrinsic accuracy of the optical frequency scale in spectra acquired by a Fourier Transform Spectrometer (FTS). The uncalibrated accuracy of the FTS optical frequency axis is about 1 part in 10⁵. This uncertainty can be reduced by at least two orders of magnitude using a multiplicative calibration correction derived from a single wavelength standard line. The work reported here describes a new approach to accurate calibration of the wavenumber scale for a UV-visible FTS, which we have used to measure accurate wavenumbers and Ar pressure shifts for the prominent lines of ¹⁹⁸Hg.

Experimental results of intelligent adaptive detection made with spectral sensors are presented. Firstly for a commercial detector array spectrometer the single entrance slit is replaced by a slit array. Differently patterned one-dimensional arrays are used. There are switched and fixed versions of arrays. An improvement of the detected signal and the signal-to-noise-ratio by the factor 10 has been achieved. Secondly the measured noisy signal is compared with known expected signals. Weak signals can be detected with an high probability and thus an increased sensitivity.

We apply optical coherence tomography (OCT) and a modification thereof, namely polarisationsensitive OCT (PS-OCT), to a variety of problems posed in metrology for material analysis and diagnostics. Among these are imaging of glass-fibre enforced epoxy resin compounds and the detection of dry spots. Furthermore, PS-OCT measurements have been used to measure the birefringence and the orientation of the fast optical axis within test structures: mapping of strain fields of samples under uni-axial and non-uniform external stress and the detection of flow patterns in injection-moulded plastic parts could be successfully demonstrated.