Fiber-optic Ring Interferometer Research Articles

On possibility of using the lowest odd harmonics of the phase modulation frequency in the output signal of the fiber-optic ring interferometer for detection of the sagnac effect

The possibility of using the lowest harmonics of the phase modulation frequency in the output signal of the fiber-optic ring interferometer (FRI) for detection of the FRI rotation angular velocity is considered. It is shown that the use of the third harmonic of the phase modulation frequency is optimal, since, in this case, the effect of insignificant admixture of the second harmonic of the phase modulation frequency on the FRI baseline shift can be completely eliminated. When processing the signal using the first or the fifth harmonic of the phase modulation frequency, it is possible to compensate for the FRI baseline shift because of its weak dependence on the phase modulation amplitude. Upon processing of the FRI output signal using higher odd harmonics of the phase modulation frequency, the signal-to-noise ratio noticeably decreases.

Investigation of a correlation fiber-optic ring interferometer based on a multimode optical fiber

Investigation of a correlation fiber-optic ring interferometer based on a multimode optical fiber

Generation of squeezed states of light with a fiber-optic ring interferometer.

Forward nondegenerate four-wave mixing in an optical-fiber ring resonator is proposed as a method to generate squeezed states of light. The nonlinear interactions are analyzed both with a self-consistent propagation-equation technique and with Fokker-Planck equations in the Glauber-Sudarshan P representation. Excellent squeezing is predicted at modest input power levels, with perfect quantum-noise squeezing at the critical points for optical bistability. A method to suppress the stimulated Brillouin effect is proposed and demonstrated experimentally, and the effects of forward spontaneous guided acoustic wave Brillouin scattering inside the resonator are analyzed. Methods are suggested for minimizing this noise under conditions where squeezing can be detected. Experimental apparatus and procedures are outlined for verifying the predictions of our theory and demonstrating squeezing of classical and quantum noise.

Contrast of a photomixing signal in a multimode ring interferometer

A simple method is proposed for determining the contrast of a photomixing signal in a fiber-optic ring interferometer. The method is based on determination of the constant component of the photocurrent in the presence and absence of harmonic phase modulation. Measurements are reported of the contrast of a photomixing signal in a multimode fiber-optic ring interferometer as a function of the number of mode groups mixed in a photodetector, length of a waveguide, and radiation wavelength. It is shown that in the case of low-index mode groups the contrast is mainly due to the intergroup exchange, whereas in the case of high-index mode groups it is due to the intragroup exchange.

Polarization stabilization in a fiber-optic ring interferometer

It is shown that a polarization stabilization system for a fiber-optic ring interferometer can be synthesized using equivalence theorems for polarization optics in the case of complete compensation of the polarizing properties and of the natural optical activity of a fiber waveguide. Two examples are considered by way of illustration.

Fiber-optic ring interferometer with a multimode waveguide

The nature of propagation of electromagnetic oscillations in a multimode waveguide is considered and it is shown in principle that such a waveguide can be used in a fiber-optic ring interferometer in combination with an optical radiation source characterized by a short coherence length. A description is given of the apparatus and the results of an experimental investigation of such an interferometer are reported. Ways of improving further the sensitivity of this interferometer are discussed.