Fig. 1. Schematic diagram of the square-shaped composite cavity coupled with a MDM waveguide containing a metal baffle

Fig. 2. Transmission spectra of side-coupled square-shaped resonator and the magnetic field patterns at two resonance wavelengths

Fig. 3. Transmission spectra of MDM waveguide side-coupled a stub contained square-shaped composite rsonator and the magnetic field patterns at four resonance wavelengths

Fig. 4. Transmission analysis of the MDM waveguide coupled with the square-shaped composite cavity with deferent S

Fig. 5. Transmission analysis of the MDM waveguide coupled with the square-shaped composite cavity with deferent stub length h

Fig. 6. Relation between transmission spectra and the refractive indexes n in the square-shaped resonator of S=300 nm

Fig. 7. Relation between transmission spectra and the refractive indexes n in the square-shaped resonator of S=300 nm and h=150 nm

Fig. 8. Relationship between transmission spectra and the refractive indexes n in the enlarged square-shaped resonator of S=360 nm and h=210 nm