Characteristics analysis of SOI waveguide Michelson interferometers for developing biomedical fiber temperature-sensing head

Abstract

A new silicon-on-insulator (SOI) waveguide Michelson interferometer with Bragg reflective gratings as a biomedical temperature sensing array head is presented in this paper. The waveguide Bragg reflective gratings work as mirrors for adjusting the transfer function of the Michelson interferometer sensor. We will show the comparison of the temperature sensing accuracies of the fiber Bragg grating and SOI waveguide Michelson interferometers in biomedical applications. The grating length and perturbation period of waveguide Bragg grating in SOI waveguide Michelson interferometer will increase as temperature rises, that is, the thermal effects of the reflective Bragg gratings are considered in our analysis. According to the numerical analysis of power reflective spectra of waveguide Michelson interferometers, the temperature sensing waveguide of the Michelson interferometer can improve at least 20 times than the traditional fiber Bragg grating temperature sensor. Moreover, the SOI waveguide interferometer sensor we designed presents high sensitivity than pure single waveguide Bragg grating sensor and fiber Bragg grating sensor by adjusting the length of the two interferometric arms. The full width of half maximum (FWHM) of the frequency responses of passband of SOI waveguide Michelson interferometer can be designed smaller than fiber and waveguide Bragg grating sensors for sensitivity improvement.