Table of contents

This review is concerned with the physical problems of fiber ring interferometry which underlies the fiber-optic gyroscopy harnessing the Sagnac effect. Locally reciprocal and locally nonreciprocal physical effects are considered, including polarization, transient, magnetic, nonlinear, and relativistic effects. These effects are responsible for the appearance of additional signals, which are similar to the rotation signal, at the output of a fiber-optic gyroscope. The causes of instability of the effects leading to the drift of the output signal are analyzed. The sources of fluctuations which limit the ultimate sensitivity of fiber gyroscopes are considered. We discuss different fields of application of fiber ring interferometers and fiber gyroscopes built around them for practical purposes and to basic research. The prospects for further development of fiber gyroscopy are considered.

Experimental data on impurity states in narrow-gap lead telluride based semiconductors are summarized. Theoretical models describing the nontrivial properties of such states are presented. Applications to the design of highly sensitive far-infrared detectors are considered.

An analysis of the current theory of the quantum oscillator phase is presented. Predictions using existing approaches to the phase problem differ not only quantitatively but also qualitatively. The question in the title has not yet been given a generally accepted answer. However, it is logical to argue that all the theoretically predicted properties of the phase are physically meaningful if appropriate measurements are possible. Current phase measurement methods either involve the simultaneous (approximate) measurement of the amplitude and the phase or rely on the simultaneous measurement of quadrature amplitudes.

A consistent procedure for plotting the carbon melting and boiling coexistence curves based on published data and the authors' experimental results is proposed. The parameters of a triple point are predicted to differ markedly from the currently accepted values: p_t ≈1 bar and T_t ≈ 4000 K. Two types of experimental facilities were used, with laser heating of samples in one and direct ohmic heating in the other. The existence of a carbyne region (a stable linear polymer consisting of carbon atoms) in the carbon phase diagram is discussed. Results on the direct solid-phase graphite – carbyne transition are presented, and this is shown to occur under certain conditions in the form of a thermal explosion.