Modified balanced-bridge switch with two straight waveguides

A new balanced‐bridge‐switch configuration is presented. This configuration has two 3‐dB couplers and an electro‐optic phase shifter formed only by two parallel straight waveguides. That is, these three regions were directly interconnected through no extra waveguides. The phase shifter was realized by unsynchronizing the phase of two adjacent waveguides by loading a high‐index film on one of them. The modified balanced‐bridge switch was fabricated in c‐plate LiNbO3 using Ti‐diffused waveguides and a Se‐S–based chalcogenide glass film. Waveguide dimensions were 8‐μm width, 5‐μm gap, and 16‐mm interaction length. Switch characteristics at 1.15‐ μm wavelength were 3.3 V half‐wave voltage, 8.7‐dB crosstalk, and 4.2‐dB insertion loss.