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Suppression of the polarization drift of optical fiber ring resonators is investigated both theoretically and experimentally by employing anisotropy in a polarization maintaining fiber ring. A general analytic expression for the transmission of the device is derived allowing the fiber modes to exhibit any combination of polarization crosstalk, differential loss or differential coupling. The analysis shows that a moderate level of ring anisotropy, such as that of 10 dB in line polarizer or polarization selective coupler, is sufficient to greatly suppress the drift of the eigenstates of polarization (ESOPs), finesse and resonant point, restoring the device's suitability for most practical applications. An inevitable consequence of introducing ring anisotropy is the loss of orthogonality of the ESOPs. This effect limits the anticipated benefit in high sensitivity applications. A practical anisotropic PMRR is demonstrated by inserting a thin film of nematic liquid crystal between the two halves of the polished coupler of the ring. This resonator demonstrates a polarization response immune to environmental perturbations.

A novel configuration for single-mode all-fiber optic, liquid crystal based intensity modulation is suggested. The electrodes have the form of two thin indium tin oxide films, one of which is directly deposited on top of the polished face of the optical fiber. Intensity modulation using nematic and ferroelectric liquid crystal is demonstrated showing that the device offers the potential for low loss (0.5 dB), high modulation depth (20 dB), and moderate drive voltages for frequencies up to several megahertz at 633-nm wavelength.

On montre que la modulation piezoelectrique non lineaire peut induire des effets de resonance parasite dans la fonction de transfert du resonateur

The transmission characteristics of a polarization-maintaining optical-fiber ring resonator are examined. The resonator’s response is found to be strongly dependent on the differential phase delay between the fiber birefringence axes. Large cross talk of as much as 40% between the fiber modes and splitting of the resonance notch can occur, even for very good (better than −35-dB) isolation between the fiber polarization modes.

An analysis of the dynamic response of a single-mode all-fiber ring resonator is presented in which a time-varying phase shift is induced in the ring by a phase modulator. In particular, the deviation of the response from that expected from the steady-state analysis is discussed.

An all-fibre polariser is demonstrated utilising the birefringent properties of a nematic liquid crystal having refractive indices compatible to that of fused silica. The polariser exhibits an extinction ratio in excess of −45dB and a loss of 0.2dB over a temperature range between 10 and 50°C. Design considerations to achieve a desired extinction ratio are also discussed.