Fig. 5: Tunable add-drop filter.
a 3-D schematic view of the out-of-plane actuated tunable add-drop filter depicting the resonant-mode behaviour of the engaged filter. b SEM recording of the released device showing the suspended ring and the two well-aligned and suspended bus waveguides on either side. c Measurement results for power transmission to the through and drop ports for both on- and off-resonance wavelengths in the two filter states. When the filter is ON (0 V), the free spectral range (FSR) is ~5 nm, and the port extinction ratio (ER) is 20.4 dB for resonant wavelengths and 13.2 dB for off-resonance wavelengths. Turning OFF the filter (27 V) maintains an ER > 20 dB for resonant wavelengths
