Phase Modulation Technique Of Interferometers Based On Coupled Resonator

As the rapid development of optics and fiber techniques, optical sensingtechniques have been widely used in both military and civil applications such asinertial navigation, guidance, biosensing, temperature sensing and so on. Thecoupled resonator technique is one of them. It has the advantages of variousstructures, compact size, high dispersion and high Q factor, and thus made thesensing technique more sensitive and highly compact. But there are many criticaltechniques to be realized about coupled resonator based interferometers, whichseverely hinder the sensing system to be applied. In this article, we firstlyanalyze the current research status at home and abroad, and then we found outthat it is the imperfection of phase modulation technology which made theoptical sensing system unusable.Firstly, based on the basic theory of coupled resonators and Sagnac effect,we build the transient response theory of coupled resonator based Sagnacinterferometer, and based on this transient response theory, we analyze theadvantage and disadvantage of coupled resonator based Sagnac interferometer.Secondly, to solve the problem that at low rotational velocity the sensitivityis almost zero, we propose a complete and effective theory of phase modulationtechnique. We theoretically prove that a phase modulation function of specificperiod and amplitude, the sensing ability of coupled resonator based Sagnacinterferometer can be obviously enhanced, which include transmissioncharacteristic, sensitivity and fiber length.At last, we investigate the coupled resonator based M-Z interferometersystem, and analyze its transmission characteristic. We introduced the phasemodulation technique into M-Z interferometer and analyze its effect on opticalsensing and switching technique both theoretically and experimentally.