Fig. 1. Schematic image of the total sensing system.

Fig. 2. (a) Electric field intensity of the waveguide for the TE mode. (b) Electric field intensity of the waveguide for the TM mode.

Fig. 3. (a) Simulated transmission spectra of the TE and TM modes. (b) Simulated wavelength shifts versus RI change for the TE and TM modes.

Fig. 4. (a) SEM image of the direction coupler. (b) Optical microscope image of the microring.

Fig. 5. (a) Microring chip. (b) Detection system.

Fig. 6. (a) Measured transmission spectra of the TM mode when the concentration of aqueous solutions of NaCl changes from 0 to 3%. (b) Measured transmission spectra of the TE mode when the concentration of aqueous solutions of NaCl changes from 0 to 3%.

Fig. 7. Measured wavelength shift versus RI change of aqueous solutions of NaCl with different concentrations for TE and TM modes.