Figure 3

Cavity refractive indices versus relative channel shift and continuous tuning of the central channel. ( a) The cavity refractive indices, $n_{\text{def}}^{(\mathbf{2}\mathbf{,}\mathbf{4}\mathbf{,}\mathbf{6})}$, versus relative channel position shift normalised to the original channel spacing. (b) Continuous tuning of the central channel for ∆n = −0.026 (red dashed line), ∆n = −0.013 (red dashed dotted line), ∆n = 0 (black line), ∆n = 0.013 (thin blue line) and ∆n = 0.026 (thick blue line).