RESUMO
Fiber-optic interferometers have been studied extensively for sensing applications. Recently a technique described as the J(1) ... J(4) technique was reported for the linear measurement of dynamic phase changes in a fiber interferometer that requires no phase bias and for which the measurement is independent of random phase fluctuations. However, the implementation of the J(1) ... J(4) technique is limited because only the magnitude of the J(1) ... J(4) Bessel components can be measured on a spectrum analyzer without information available on the sign of the Bessel function. Here a modified signal-processing technique that overcomes the limitations mentioned above is described.
RESUMO
A simple analysis is presented for calculating the change in the effective index of a guided mode in an optical fiber with reduced cladding surrounded by an optically nonlinear medium. Using first-order perturbation theory, the optical power required to alter the phase-matched condition in a fiber directional coupler incorporating a nonlinear medium is therefore calculated. This may then be applied to an optically controlled switch, the output of which may be transferred from one port to another by application of a high-intensity pulse. This method may be applied to other fiber components, for example, fiber gratings and polarizers.
