Fig. 2
From: Large-scale optical switches by thermo-optic waveguide lens
a The experimental setup to monitor the imaging effect of TOWL. b The photo of the TOWL chip with an open multimode waveguide facet. c The captured near-field intensity profile for the electrode pair H6 + H11 under different heating currents. The center line of the parallel electrodes H6 + H11 is considered as the optical axis of the lens and is aligned with the input waveguide for the on-axis imaging (y = 0). d The simulation and experimental results show the TOWL driven by the electrode pair H3 + H9, where the optical axis is shifted to y = + 15 μm. Correspondingly, the off-axis imaging has resulted in a focused spot at y = + 30 μm. e The results under the electrode pair H8 + H14, where the optical axis is shifted to y = -15 μm. Correspondingly, the off-axis imaging has resulted in a focused spot at y = -30 μm