Fig. 1. Schematic of proposed structure. Inset, ridge waveguide cross-section view; BOX, buried oxide layer; L, coupling length; κ(κ0), coupling coefficient; r(r0), self-coupling coefficient.

Fig. 2. (a) Resonance splitting in dual-ring structure. (b) Resonance wavelength detuning at different ring-to-ring coupling coefficient. λ0 is the central wavelength, representing resonance wavelength at κ=0; λ is the resonance wavelength; FSR stands for free spectral range. (c) dλ/dκ with respect to coupling coefficient, approximately constant in a wide range of κ=0–0.7.

Fig. 3. Numerical analysis of (a) energy flux density (Pz) and (b) field Hy distribution in DC.

Fig. 4. (a) Relations of coupling coefficient κ and (b) temperature sensitivity of coupling coefficient (dκ/dT) versus coupling length at different temperature. Dots, simulation results; line, fitting curve based on coupled mode theory.

Fig. 5. Transmission spectra (a) without and (b) with resonance splitting.

Fig. 6. Relations of blue shift (blue line and dots) and resonance wavelength shift (red line and crosses) versus temperature. λ0 is the resonance wavelength at T=300  K, and λ is resonance wavelength.