Influence of ambient refractive index on radiation modes
To explore fibre refractive index (RI) sensing based on radiation modes, the influences of ambient RI on radiation modes are investigated by a leaky mode approximation in a two-layer fibre. Based on the analytical analysis and simulation results, it is identified that the change of ambient RI has no effect on the real part of the complex propagation constant of a leaky mode, but a remarkable effect on the imaginary part. More importantly, the influence of the medium's absorption loss on the imaginary part is almost negligible. If the medium's absorption loss is lower than 3.521 × 103 dB/cm, the induced average deviation rate of the imaginary part is <1.91%.
