Fig. 1. Micro-nano fiber coupler structure

Fig. 2. The distribution of light field and the energy transmission of two arms of coupler at different coupling degrees

Fig. 3. The process of adjusting the spectral extinction ratio when the polarization angle adjustment range is 0～90°

Fig. 4. The output transmission spectrum of polarization controller half wave plate when the deflection angle is 0～90°

Fig. 5. Polarization controller half plate deflection angle and extinction analogy diagram

Fig. 6. Output comb spectrum of micro-nano coupled ring mirror with different length of waist cone

Fig. 7. The experimental setup of liquid refractive index

Fig. 8. The spectrum of the micro-nano coupled ring mirror is regulated by the refractive index of the surrounding liquid