Fig. 7
From: Tunable narrow-band single-channel add-drop integrated optical filter with ultrawide FSR
Simulations of the design with the improved drop efficiency. a Simulated phase difference of the drop ports of the proposed ADF. The yellow star shows the resonance wavelength position. b Simulated transmission spectra of the improved device combining the 2 × 2 adiabatic splitter and the proposed ADF at the output port (Drop port). The insert shows the schematic of the improved device design