Electro-optic Waveguide Stretches Suppress Edge Effects

The patent applies local quality by forming stretches of the high-refractive-index layers that extend beyond the slot part in the width direction. This creates regions with different functional properties: the central region confines light in the slot, while the stretched regions at the edges generate electric fields that counteract the edge effect and maintain uniform electric field intensity across the slot, thereby improving phase modulation efficiency without compromising light confinement.

By forming stretches of the high-refractive-index layers that extend beyond the slot part, the patent creates local regions that generate electric fields specifically targeted at counteracting the edge effect. This local intervention maintains uniform electric field intensity across the narrowed slot width, enabling single lateral mode propagation while mitigating the increased edge effect influence that would otherwise occur.

The patent forms stretches of the high-refractive-index layers that extend beyond the slot part. These stretched regions can be selectively doped to provide necessary conductivity for electric field generation, while the central slot region maintains optimal optical properties. This spatial separation of functions allows conductivity enhancement in the stretch regions without increasing optical loss in the light-confining slot region.