Study on characteristics of fiber loop mirror filters based on single fiber Mach-Zehnder (M-Z) optimization

In the single-mode fiber pull cascaded symmetric slow taper, formation of Mach-Zehnder (M-Z) interferometer, put it into the fiber loop mirror. Theoretical and experimental study on the improvement of its filter characteristics. Loop mirror filter of transmission by M-Z interference and Sagnac interferometer combined with non-coherent superposition, and tuning M-Z interferometer to achieve its tunable filter. Experiments show that the filter can be tuned in the range of 60 nm, stable output waveforms, modulation depth greater than 20 dB, optimization of the structure of fiber loop mirror filter characteristics.